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Polyurethane U-Seal, 4.00 Inch OD, 3.50 Inch ID, 0.25 Inch Height

Description & Features

This Hercules Sealing Products U-Seal is constructed from durable polyurethane for reliable sealing in demanding hydraulic applications. With a 4.00 inch outer diameter and a 3.50 inch inner diameter, this U-Seal is designed for a secure fit. The beveled lip design of this seal provides superior film breaking.

This Polyurethane U-Seal offers dependable performance across a broad temperature range, from -65°F to 220°F, and is capable of handling pressures from 0 to 6,000 PSI. Its 0.25 inch height and cross-section make it suitable for applications where height and cross-section are equal.

SKU: U25-3.50-SQB

Supplier Part Number (MPN): U25-3.50-SQB

Alternate Part Numbers: C1DP50, MI-01011219, MINO-00407X25229

Specifications

Cross Section 0.25 in	Brand Hercules Sealing Products	Brand Hercules Sealing Products	Pack Size 1.00	UOM EA	H 0.25 in	I.D. 3.5 in	O.D. 4 in	Supplier Part Number U25-3.50-SQB	Alternate Part Numbers Alternate Part Number C1DP50, Alternate Part Number MI-01011219, Alternate Part Number MINO-00407X25229	Product Weight 0.04 lbs

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Model Number	Cross Section	I.D.	O.D.	H
U12-0.62-25B Polyurethane U-Seal	0.125 in	0.625 in	0.875 in	0.25 in
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U18-1.25-SQB Polyurethane U-Seal	0.1875 in	1.25 in	1.625 in	0.1875 in
U18-1.75-37B Polyurethane U-Seal	0.1875 in	1.75 in	2.125 in	0.375 in
U18-2.12-SQB Polyurethane U-Seal	0.1875 in	2.125 in	2.5 in	0.1875 in
U18-2.50-31B Polyurethane U-Seal	0.1875 in	2.5 in	2.875 in	0.3125 in
U25-1.25-37B Polyurethane U-Seal	0.25 in	1.25 in	1.75 in	0.375 in
U25-1.50-37B Polyurethane U-Seal	0.25 in	1.5 in	2 in	0.375 in
U25-2.00-37B Polyurethane U-Seal	0.25 in	2 in	2.5 in	0.375 in
U25-2.50-37B Polyurethane U-Seal	0.25 in	2.5 in	3 in	0.375 in
U25-3.00 Polyurethane U-Seal	0.25 in	3 in	3.5 in	0.25 in
U25-3.00-37B Polyurethane U-Seal	0.25 in	3 in	3.5 in	0.375 in
U25-3.50-37B Polyurethane U-Seal	0.25 in	3.5 in	4 in	0.375 in
U25-4.00-SQB Polyurethane U-Seal	0.25 in	4 in	4.5 in	0.25 in
U25-4.50 Polyurethane U-Seal	0.25 in	4.5 in	5 in	0.25 in
U25-5.00 Polyurethane U-Seal	0.25 in	5 in	5.5 in	0.25 in
U12-0.18-25B Polyurethane U-Seal	0.125 in	0.1875 in	0.438 in	0.25 in
U12-0.25-25B Polyurethane U-Seal	0.125 in	0.25 in	0.5 in	0.25 in
U12-0.25-SQB Polyurethane U-Seal	0.125 in	0.25 in	0.5 in	0.125 in
U12-0.31-25B Polyurethane U-Seal	0.125 in	0.3125 in	0.563 in	0.25 in
U12-0.31-SQB Polyurethane U-Seal	0.125 in	0.3125 in	0.563 in	0.125 in
U12-0.37 Polyurethane U-Seal	0.125 in	0.375 in	0.625 in	0.125 in
U12-0.50-25B Polyurethane U-Seal	0.125 in	0.5 in	0.75 in	0.25 in
U12-0.50-SQB Polyurethane U-Seal	0.125 in	0.5 in	0.75 in	0.125 in
U12-0.56 Polyurethane U-Seal	0.125 in	0.625 in	0.938 in	0.125 in
U12-0.62-SQB Polyurethane U-Seal	0.125 in	0.625 in	0.875 in	0.125 in
U12-0.68 Polyurethane U-Seal	0.125 in	0.6875 in	0.938 in	0.125 in
U12-0.75-18B Polyurethane U-Seal	0.125 in	0.75 in	1 in	0.1875 in
U12-0.75-25B Polyurethane U-Seal	0.125 in	0.75 in	1 in	0.25 in
U12-0.75-SQB Polyurethane U-Seal	0.125 in	0.75 in	1 in	0.125 in
U12-0.81 Polyurethane U-Seal	0.125 in	0.8125 in	1.063 in	0.125 in
U12-0.87-25B Polyurethane U-Seal	0.125 in	0.875 in	1.125 in	0.25 in
U12-0.87-SQB Polyurethane U-Seal	0.125 in	0.875 in	1.125 in	0.125 in
U12-1.00-18B Polyurethane U-Seal	0.125 in	1 in	1.25 in	0.1875 in
U12-1.00-SQB Polyurethane U-Seal	0.125 in	1 in	1.25 in	0.125 in
U12-1.06-SQB Polyurethane U-Seal	0.125 in	1.0625 in	1.313 in	0.125 in
U12-1.12-25B Polyurethane U-Seal	0.125 in	1.0625 in	1.375 in	0.25 in
U12-1.12-SQB Polyurethane U-Seal	0.125 in	1.0625 in	1.375 in	0.125 in
U12-1.18 Polyurethane U-Seal	0.125 in	0.188 in	1.438 in	0.125 in
U12-1.18-18B Polyurethane U-Seal	0.125 in	0.188 in	1.438 in	0.1875 in
U12-1.18-25B Polyurethane U-Seal	0.125 in	0.188 in	1.438 in	0.25 in
U12-1.25-18B Polyurethane U-Seal	0.125 in	1.25 in	1.5 in	0.1875 in
U12-1.25-25B Polyurethane U-Seal	0.125 in	1.25 in	1.5 in	0.25 in
U12-1.37-25B Polyurethane U-Seal	0.125 in	1.375 in	1.625 in	0.25 in
U12-1.37-SQB Polyurethane U-Seal	0.125 in	1.375 in	1.625 in	0.125 in
U12-1.50-25B Polyurethane U-Seal	0.125 in	1.5 in	1.75 in	0.25 in
U12-1.50-SQB Polyurethane U-Seal	0.125 in	1.5 in	1.75 in	0.125 in
U12-1.62-SQB Polyurethane U-Seal	0.125 in	1.625 in	1.875 in	0.125 in
U12-1.75-SQB Polyurethane U-Seal	0.125 in	1.75 in	2 in	0.125 in
U12-2.00 Polyurethane U-Seal	0.125 in	2 in	2.25 in	0.125 in
U12-2.25 Polyurethane U-Seal	0.125 in	2.25 in	2.5 in	0.125 in
U12-2.75 Polyurethane U-Seal	0.125 in	2.75 in	3 in	0.125 in
U15-1.18 Polyurethane U-Seal	0.1563 in	0.188 in	1.5 in	0.1563 in
U15-1.25 Polyurethane U-Seal	0.1563 in	1.25 in	1.563 in	0.1563 in
U15-1.37 Polyurethane U-Seal	0.1563 in	1.375 in	1.688 in	0.1563 in
U18-0.50 Polyurethane U-Seal	0.1875 in	0.5 in	0.875 in	0.1875 in
U18-0.62-31B Polyurethane U-Seal	0.1875 in	0.625 in	1 in	0.3125 in
U18-0.62-SQB Polyurethane U-Seal	0.1875 in	0.625 in	1 in	0.1875 in
U18-0.75-31B Polyurethane U-Seal	0.1875 in	0.75 in	1.125 in	0.3125 in
U18-0.75-SQB Polyurethane U-Seal	0.1875 in	0.75 in	1.125 in	0.1875 in
U18-0.87-31B Polyurethane U-Seal	0.1875 in	0.875 in	1.25 in	0.3125 in
U18-0.87-SQB Polyurethane U-Seal	0.1875 in	0.875 in	1.25 in	0.1875 in
U18-1.00-25B Polyurethane U-Seal	0.1875 in	1 in	1.375 in	0.25 in
U18-1.00-31B Polyurethane U-Seal	0.1875 in	1 in	1.375 in	0.3125 in
U18-1.00-37B Polyurethane U-Seal	0.1875 in	1 in	1.375 in	0.375 in
U18-1.00-SQB Polyurethane U-Seal	0.1875 in	1 in	1.375 in	0.1875 in
U18-1.12-25B Polyurethane U-Seal	0.1875 in	1.0625 in	1.5 in	0.25 in
U18-1.12-31B Polyurethane U-Seal	0.1875 in	1.0625 in	1.5 in	0.3125 in
U18-1.12-SQB Polyurethane U-Seal	0.1875 in	1.0625 in	1.5 in	0.1875 in
U18-1.18 Polyurethane U-Seal	0.1875 in	0.188 in	1.563 in	0.1875 in
U18-1.25-25B Polyurethane U-Seal	0.1875 in	1.25 in	1.625 in	0.25 in
U18-1.25-31B Polyurethane U-Seal	0.1875 in	1.25 in	1.625 in	0.3125 in
U18-1.25-37B Polyurethane U-Seal	0.1875 in	1.25 in	1.625 in	0.375 in
U18-1.37-25B Polyurethane U-Seal	0.1875 in	1.375 in	1.75 in	0.25 in
U18-1.37-31B Polyurethane U-Seal	0.1875 in	1.375 in	1.75 in	0.3125 in
U18-1.37-37B Polyurethane U-Seal	0.1875 in	1.375 in	1.75 in	0.375 in
U18-1.37-SQB Polyurethane U-Seal	0.1875 in	1.375 in	1.75 in	0.1875 in
U18-1.50-25B Polyurethane U-Seal	0.1875 in	1.5 in	1.875 in	0.25 in
U18-1.50-31B Polyurethane U-Seal	0.1875 in	1.5 in	1.875 in	0.3125 in
U18-1.50-37B Polyurethane U-Seal	0.1875 in	1.5 in	1.875 in	0.375 in
U18-1.50-SQB Polyurethane U-Seal	0.1875 in	1.5 in	1.875 in	0.1875 in
U18-1.62 Polyurethane U-Seal	0.1875 in	1.625 in	2 in	0.1875 in
U18-1.62-25B Polyurethane U-Seal	0.1875 in	1.625 in	2 in	0.25 in
U18-1.62-31B Polyurethane U-Seal	0.1875 in	1.625 in	2 in	0.3125 in
U18-1.62-37B Polyurethane U-Seal	0.1875 in	1.625 in	2 in	0.375 in
U18-1.62-SQB Polyurethane U-Seal	0.1875 in	1.625 in	2 in	0.1875 in
U18-1.75-25B Polyurethane U-Seal	0.1875 in	1.75 in	2.125 in	0.25 in
U18-1.75-31B Polyurethane U-Seal	0.1875 in	1.75 in	2.125 in	0.3125 in
U18-1.75-SQB Polyurethane U-Seal	0.1875 in	1.75 in	2.125 in	0.1875 in
U18-1.87-37B Polyurethane U-Seal	0.1875 in	1.875 in	2.25 in	0.375 in
U18-1.87-SQB Polyurethane U-Seal	0.1875 in	1.875 in	2.25 in	0.1875 in
U18-2.00-31B Polyurethane U-Seal	0.1875 in	2 in	2.375 in	0.3125 in
U18-2.00-37B Polyurethane U-Seal	0.1875 in	2 in	2.375 in	0.375 in
U18-2.00-SQB Polyurethane U-Seal	0.1875 in	2 in	2.375 in	0.1875 in
U18-2.12-25B Polyurethane U-Seal	0.1875 in	2.125 in	2.5 in	0.25 in
U18-2.25-37B Polyurethane U-Seal	0.1875 in	2.25 in	2.625 in	0.375 in
U18-2.25-SQB Polyurethane U-Seal	0.1875 in	2.25 in	2.625 in	0.1875 in
U18-2.37-SQB Polyurethane U-Seal	0.1875 in	2.375 in	2.75 in	0.1875 in
U18-2.50-25B Polyurethane U-Seal	0.1875 in	2.5 in	2.875 in	0.25 in
U18-2.50-37B Polyurethane U-Seal	0.1875 in	2.5 in	2.875 in	0.375 in
U18-2.50-SQB Polyurethane U-Seal	0.1875 in	2.5 in	2.875 in	0.1875 in
U18-2.62-37B Polyurethane U-Seal	0.1875 in	2.625 in	3 in	0.375 in
U18-2.62-SQB Polyurethane U-Seal	0.1875 in	2.625 in	3 in	0.1875 in
U18-2.75-37B Polyurethane U-Seal	0.1875 in	2.75 in	3.125 in	0.375 in
U18-2.75-SQB Polyurethane U-Seal	0.1875 in	2.75 in	3.125 in	0.1875 in
U18-2.87 Polyurethane U-Seal	0.1875 in	2.875 in	3.25 in	0.1875 in
U18-3.00 Polyurethane U-Seal	0.1875 in	3 in	3.375 in	0.1875 in
U18-3.00-37B Polyurethane U-Seal	0.1875 in	3 in	3.375 in	0.375 in
U18-3.12-37B Polyurethane U-Seal	0.1875 in	3.125 in	3.5 in	0.375 in
U18-3.12-SQB Polyurethane U-Seal	0.1875 in	3.125 in	3.5 in	0.1875 in
U18-3.50-37B Polyurethane U-Seal	0.1875 in	3.5 in	3.875 in	0.375 in
U18-3.62-37B Polyurethane U-Seal	0.1875 in	3.625 in	4 in	0.375 in
U18-3.62-SQB Polyurethane U-Seal	0.1875 in	3.625 in	4 in	0.1875 in
U18-4.00-37B Polyurethane U-Seal	0.1875 in	4 in	4.375 in	0.375 in
U25-0.75 Polyurethane U-Seal	0.25 in	0.75 in	1.25 in	0.25 in
U25-0.93 Polyurethane U-Seal	0.25 in	0.8125 in	1.438 in	0.25 in
U25-1.00-37B Polyurethane U-Seal	0.25 in	1 in	1.5 in	0.375 in
U25-1.00-SQB Polyurethane U-Seal	0.25 in	1 in	1.5 in	0.25 in
U25-1.12 Polyurethane U-Seal	0.25 in	1.0625 in	1.625 in	0.25 in
U25-1.12-37B Polyurethane U-Seal	0.25 in	1.0625 in	1.625 in	0.375 in
U25-1.18 Polyurethane U-Seal	0.25 in	0.188 in	1.688 in	0.25 in
U25-1.25-SQB Polyurethane U-Seal	0.25 in	1.25 in	1.75 in	0.25 in
U25-1.37 Polyurethane U-Seal	0.25 in	1.375 in	1.875 in	0.25 in
U25-1.37-37B Polyurethane U-Seal	0.25 in	1.375 in	1.875 in	0.375 in
U25-1.50-31B Polyurethane U-Seal	0.25 in	1.5 in	2 in	0.3125 in
U25-1.50-SQB Polyurethane U-Seal	0.25 in	1.5 in	2 in	0.25 in
U25-1.75 Polyurethane U-Seal	0.25 in	1.75 in	2.25 in	0.25 in
U25-1.75-37B Polyurethane U-Seal	0.25 in	1.75 in	2.25 in	0.375 in
U25-1.87-37B Polyurethane U-Seal	0.25 in	1.875 in	2.375 in	0.375 in
U25-2.00-31B Polyurethane U-Seal	0.25 in	2 in	2.5 in	0.3125 in
U25-2.00-SQB Polyurethane U-Seal	0.25 in	2 in	2.5 in	0.25 in
U25-2.12-37B Polyurethane U-Seal	0.25 in	2.125 in	2.625 in	0.375 in
U25-2.25 Polyurethane U-Seal	0.25 in	2.25 in	2.75 in	0.25 in
U25-2.25-37B Polyurethane U-Seal	0.25 in	2.25 in	2.75 in	0.375 in
U25-2.37-37B Polyurethane U-Seal	0.25 in	2.375 in	2.875 in	0.375 in
U25-2.50-SQB Polyurethane U-Seal	0.25 in	2.5 in	3 in	0.25 in
U25-2.62-37B Polyurethane U-Seal	0.25 in	2.625 in	3.125 in	0.375 in
U25-2.75-37B Polyurethane U-Seal	0.25 in	2.75 in	3.25 in	0.375 in
U25-2.75-SQB Polyurethane U-Seal	0.25 in	2.75 in	3.25 in	0.25 in
U25-3.25-37B Polyurethane U-Seal	0.25 in	3.25 in	3.75 in	0.375 in
U25-3.50 Polyurethane U-Seal	0.25 in	3.5 in	4 in	0.25 in
U25-3.50-SQB Polyurethane U-Seal	0.25 in	3.5 in	4 in	0.25 in
U25-3.75-37B Polyurethane U-Seal	0.25 in	3.75 in	4.25 in	0.375 in
U25-3.75-SQB Polyurethane U-Seal	0.25 in	3.75 in	4.25 in	0.25 in
U25-4.00-37B Polyurethane U-Seal	0.25 in	4 in	4.5 in	0.375 in
U25-4.00-50D Polyurethane U-Seal	0.25 in	4 in	4.5 in	0.5 in
U25-4.00-56B Polyurethane U-Seal	0.25 in	4 in	4.5 in	0.5625 in
U25-4.50-37B Polyurethane U-Seal	0.25 in	4.5 in	5 in	0.375 in
U25-4.50-56B Polyurethane U-Seal	0.25 in	4.5 in	5 in	0.5625 in
U25-4.50-62B Polyurethane U-Seal	0.25 in	4.5 in	5 in	0.625 in
U25-5.00-37B Polyurethane U-Seal	0.25 in	5 in	5.5 in	0.375 in
U25-5.50 Polyurethane U-Seal	0.25 in	5.5 in	6 in	0.25 in
U25-5.50-37B Polyurethane U-Seal	0.25 in	5.5 in	6 in	0.375 in
U25-5.50-56B Polyurethane U-Seal	0.25 in	5.5 in	6 in	0.5625 in
U31-1.00-50B Polyurethane U-Seal	0.3125 in	1 in	1.625 in	0.5 in
U31-1.25 Polyurethane U-Seal	0.3125 in	1.25 in	1.875 in	0.3125 in
U31-1.25-37B Polyurethane U-Seal	0.3125 in	1.25 in	1.875 in	0.375 in
U31-1.37-37B Polyurethane U-Seal	0.3125 in	1.375 in	2 in	0.375 in
U31-1.37-SQB Polyurethane U-Seal	0.3125 in	1.375 in	2 in	0.3125 in
U31-1.50 Polyurethane U-Seal	0.3125 in	1.5 in	2.125 in	0.3125 in
U31-1.75-37B Polyurethane U-Seal	0.3125 in	1.75 in	2.375 in	0.375 in
U31-1.87 Polyurethane U-Seal	0.3125 in	1.875 in	2.5 in	0.3125 in
U31-2.00 Polyurethane U-Seal	0.3125 in	2 in	2.625 in	0.3125 in
U31-2.00-50B Polyurethane U-Seal	0.3125 in	2 in	2.625 in	0.5 in
U31-2.25-50B Polyurethane U-Seal	0.3125 in	2.25 in	2.875 in	0.5 in
U31-2.37 Polyurethane U-Seal	0.3125 in	2.375 in	3 in	0.3125 in
U31-2.50 Polyurethane U-Seal	0.3125 in	2.5 in	3.125 in	0.3125 in
U31-2.50-50B Polyurethane U-Seal	0.3125 in	2.5 in	3.125 in	0.5 in
U31-2.75 Polyurethane U-Seal	0.3125 in	2.75 in	3.375 in	0.3125 in
U31-2.75-50B Polyurethane U-Seal	0.3125 in	2.75 in	3.375 in	0.5 in
U31-2.87 Polyurethane U-Seal	0.3125 in	2.875 in	3.5 in	0.3125 in
U31-3.00-50B Polyurethane U-Seal	0.3125 in	3 in	3.625 in	0.5 in
U31-3.37-50B Polyurethane U-Seal	0.3125 in	3.375 in	4 in	0.5 in
U31-4.00 Polyurethane U-Seal	0.3125 in	4 in	4.625 in	0.3125 in
U31-4.00-56B Polyurethane U-Seal	0.3125 in	4 in	4.625 in	0.5625 in
U31-4.37 Polyurethane U-Seal	0.3125 in	4.375 in	5 in	0.3125 in
U31-4.50 Polyurethane U-Seal	0.3125 in	4.5 in	5.125 in	0.3125 in
U37-1.25 Polyurethane U-Seal	0.375 in	1.25 in	2 in	0.375 in
U37-1.75 Polyurethane U-Seal	0.375 in	1.75 in	2.5 in	0.375 in
U37-2.50-50B Polyurethane U-Seal	0.375 in	2.5 in	3.25 in	0.5 in
U37-2.75 Polyurethane U-Seal	0.375 in	2.75 in	3.5 in	0.375 in
U37-3.25-50B Polyurethane U-Seal	0.375 in	3.25 in	4 in	0.5 in
U37-3.50 Polyurethane U-Seal	0.375 in	3.5 in	4.25 in	0.375 in
U37-3.75-50D Polyurethane U-Seal	0.375 in	3.75 in	4.5 in	0.5 in
U37-4.00-62B Polyurethane U-Seal	0.375 in	4 in	4.75 in	0.625 in
U37-4.25-50D Polyurethane U-Seal	0.375 in	4.25 in	5 in	0.5 in
U37-4.25-62B Polyurethane U-Seal	0.375 in	4.25 in	5 in	0.625 in
U37-4.25-SQB Polyurethane U-Seal	0.375 in	4.25 in	5 in	0.375 in
U37-4.50-62B Polyurethane U-Seal	0.375 in	4.5 in	5.25 in	0.625 in
U37-5.00-62B Polyurethane U-Seal	0.375 in	5 in	5.75 in	0.625 in
U37-5.25 Polyurethane U-Seal	0.375 in	5.25 in	6 in	0.375 in
U37-5.25-50D Polyurethane U-Seal	0.375 in	5.25 in	6 in	0.5 in
U37-6.25-50D Polyurethane U-Seal	0.375 in	6.25 in	7 in	0.5 in
U50-2.00-SQB Polyurethane U-Seal	0.5 in	2 in	3 in	0.5 in
U50-2.50 Polyurethane U-Seal	0.5 in	2.5 in	3.5 in	0.5 in

Product Questions & Answers (3)

Question by: Donna D on Apr 7, 2025, 8:01 PM

Does this seal hold up alright in systems running close to that 6,000 PSI ceiling, or is that more of a theoretical max?

Answer by: Customer Support on Apr 9, 2025, 6:18 AM

Polyurethane handles high-pressure hydraulic duty pretty well as a material, and the rated range for this seal runs from 0 all the way to 6,000 PSI. That upper figure is the published limit, so running near it isn't operating outside spec. That said, sustained operation at peak pressure puts more wear on any seal over time, same as any other component in a high-load hydraulic system.

Question by: Keith P on Nov 8, 2025, 4:30 PM

What kind of temps can this seal handle, cause it gets pretty hot where I'm working.

Answer by: Customer Support on Nov 10, 2025, 7:27 AM

This Hercules U-seal is good for use in temperatures ranging from -65°F to 220°F.

Question by: Lyle E on May 7, 2025, 6:51 PM

got a cylinder that takes a 3.50 ID u-seal, is this one the right size or am i readin it backwards

Answer by: Customer Support on May 9, 2025, 4:00 PM

Fit comes down to the seal dimensions. This U-seal is 3.50 inch ID, 4.00 inch OD, with a 0.25 inch cross section and 0.25 inch height, so it matches setups calling for those exact measurements.