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HERCULES ORING

Description & Features

This Hercules O-ring is a sealing solution with a 6.73-inch actual inner diameter and a 7.28-inch actual outer diameter. It has an actual width of 0.28 inches, corresponding to a nominal width of 1/4 inch. The nominal inner diameter is 6-3/4 inches, and the nominal outer diameter is 7-1/4 inches.

SKU: 568-440

Supplier Part Number (MPN): 568-440

Alternate Part Numbers: A-440, C1CG64

Specifications

Actual I.D. 6.73 Inch	Actual O.D. 7.28 Inch	Actual Width 0.28 Inch	Alternate Part Numbers Alternate Part Number A-440, Alternate Part Number C1CG64	Brand Hercules Sealing Products	Brand Hercules Sealing Products	Pack Size 1.00	UOM EA	Nominal I.D. (in) 6-3/4	Nominal O.D. 7-1/4	Nominal Width 1/4	Supplier Part Number 568-440	Product Weight 0.06 lbs

Product Questions & Answers (2)

Question by: Bobby H on Oct 14, 2025, 10:45 AM

what's the actual inner diameter on this o-ring, the nominal size don't always tell the whole story

Answer by: Customer Support on Oct 15, 2025, 5:25 PM

Actual inner diameter measures 6.73 inches. The nominal calls it 6-3/4, but if you're fitting to a machined surface or a specific bore, that 6.73 is the number you want to work from. Outer diameter comes in at 7.28 inches actual, with a width of 0.28 inches, which lines up with a 1/4-inch nominal cross-section.

Question by: Hank A on Mar 2, 2026, 7:27 AM

trying to match up an old seal, what are the actual measurements on this Hercules o-ring?

Answer by: Customer Support on Mar 3, 2026, 11:39 AM

Actual size on this one is 6.73 inch inner diameter, 7.28 inch outer diameter, and 0.28 inch width.