Catalog Hardware O-Rings and O-Ring Kits O-rings and O-ring kits help ensure a tight seal to prevent air and fluid leaks in applications such as air conditioner repair or plumbing installations. ◀◀ ◀ ▶ ▶▶ O-Ring: 169, 7 1/2 in Nominal Inside Dia., 7 11/16 in Nominal Outside Dia., 90 Shore A, Black, 2 PK O-Ring: 348, 4 3/8 in Nominal Inside Dia., 4 3/4 in Nominal Outside Dia., 75 Shore A, Brown, 2 PK O-Ring: 336, 2 7/8 in Nominal Inside Dia., 3 1/4 in Nominal Outside Dia., 75 Shore A, Brown O-Ring: 185 mm Nominal Inside Dia., 195 mm Nominal Outside Dia., 195 mm Actual Outside Dia., Black O-Ring: 022, 1 in Nominal Inside Dia., 1 1/8 in Nominal Outside Dia., 1.129 in Actual Outside Dia. O-Ring: 18 mm Nominal Inside Dia., 23 mm Nominal Outside Dia., 23 mm Actual Outside Dia., 100 PK O-Ring: 25.2 mm Nominal Inside Dia., 32.2 mm Nominal Outside Dia., 70 Shore A, Black, 25 PK O-Ring: 80 mm Nominal Inside Dia., 85 mm Nominal Outside Dia., 85 mm Actual Outside Dia., Std, 5 PK O-Ring: 110, 3/8 in Nominal Inside Dia., 9/16 in Nominal Outside Dia., 0.568 in Actual Outside Dia. Backup Ring, Contoured: Buna N, For 356, 0.076 in Thick, 0.262 in Radius, 10 PK O-Ring: 55 mm Nominal Inside Dia., 59 mm Nominal Outside Dia., 59 mm Actual Outside Dia., 5 PK O-Ring: 15 mm Nominal Inside Dia., 19 mm Nominal Outside Dia., 19 mm Actual Outside Dia., Std, 10 PK Backup Ring, Contoured: Buna N, For 167, 0.053 in Thick, 0.129 in Radius, 5 PK O-Ring: 7 mm Nominal Inside Dia., 9 mm Nominal Outside Dia., 9 mm Actual Outside Dia., Red, 50 PK O-Ring: 231, 2 5/8 in Nominal Inside Dia., 2 7/8 in Nominal Outside Dia., 90 Shore A, Black, 10 PK Backup Ring, Contoured: Buna N, For 312, 0.076 in Thick, 0.262 in Radius, 100 PK O-Ring: 218, 1 1/4 in Nominal Inside Dia., 1 1/2 in Nominal Outside Dia., 75 Shore A, Black, Inch O-Ring: 442, 7 1/4 in Nominal Inside Dia., 7 3/4 in Nominal Outside Dia., 70 Shore A, Black, 2 PK O-Ring: 115, 11/16 in Nominal Inside Dia., 7/8 in Nominal Outside Dia., 70 Shore A, Black, X, 100 PK O-Ring: 13/64 in Nominal Inside Dia., 0.308 in Actual Outside Dia., 55 Shore D, White, 50 PK ◀◀ ◀ ▶ ▶▶