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Polyurethane U-Seal, 3.50 Inch OD, 3.13 Inch ID, 0.19 Inch Height

Description & Features

Designed for hydraulic cylinder and linear actuator applications, the Polyurethane U-Seal, 3.50 Inch OD, 3.13 Inch ID, 0.19 Inch Height is a beveled-lip rod or piston seal suited for demanding fluid power environments. The beveled lip geometry promotes effective film breaking, supporting consistent sealing performance across a wide range of operating conditions.

Manufactured from urethane, this seal handles pressures from 0 to 6,000 PSI and operates across a temperature range of -65°F to 220°F. With an OD of 3.500 in, an ID of 3.125 in, and a cross section of 0.1875 in, the height and cross section are equal, consistent with the standard SQB profile. Supplied by Hercules Sealing Products, it is a dependable choice for replacement or maintenance use in hydraulic systems requiring a proven U-seal configuration.

SKU: U18-3.12-SQB

Supplier Part Number (MPN): U18-3.12-SQB

Alternate Part Numbers: C1DN82, MI-01198699, MINO-00407X60428

Specifications

Cross Section 0.1875 in	Brand Hercules Sealing Products	Brand Hercules Sealing Products	Pack Size 1.00	UOM EA	H 0.1875 in	I.D. 3.125 in	O.D. 3.5 in	Supplier Part Number U18-3.12-SQB	Alternate Part Numbers Alternate Part Number C1DN82, Alternate Part Number MI-01198699, Alternate Part Number MINO-00407X60428	Product Weight 0.02 lbs

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Model Number	Cross Section	I.D.	O.D.	H
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U25-1.25-37B Polyurethane U-Seal	0.25 in	1.25 in	1.75 in	0.375 in
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U25-2.00-37B Polyurethane U-Seal	0.25 in	2 in	2.5 in	0.375 in
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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
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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
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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
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U12-1.50-SQB Polyurethane U-Seal	0.125 in	1.5 in	1.75 in	0.125 in
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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
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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
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U18-0.87-31B Polyurethane U-Seal	0.1875 in	0.875 in	1.25 in	0.3125 in
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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 (2)

Question by: Rhonda A on May 13, 2025, 2:20 PM

what's the pressure rating on this seal? got a cylinder running pretty hard and need to know it'll hold up

Answer by: Customer Support on May 15, 2025, 6:13 AM

Urethane construction on this one handles anywhere from 0 up to 6,000 PSI, so it covers most heavy-duty hydraulic cylinder work without issue. The beveled lip geometry also helps it maintain a consistent seal under load rather than just relying on static compression.

Question by: Diane D on Jan 25, 2026, 4:24 PM

got a cylinder that takes a 3.125 bore seal, is this u-seal the one with 3.50 OD and about 3/16 thick?

Answer by: Customer Support on Jan 27, 2026, 3:25 PM

The key dimensions on this one are 3.500 inch OD, 3.125 inch ID, and a 0.1875 inch cross section with the same 0.1875 inch height, which matches the SQB profile. If those numbers line up with what you pulled out, it is the right size family.