SealSpec / O-rings / Size chart / AS568-278

AS568-278 O-ring · 12 ID × 1/8 cross-section

Standard AS568 size -278: 11.984 in inside diameter × 0.139 in cross-section (304.39 × 3.53 mm). Dimensions, tolerances, groove check and material options for specifying this size in a production design.

AS568-278 O-ring dimensioned drawing, 11.984 inch ID by 0.139 inch cross-section, outside diameter 12.262 inch — Dimensioned drawing, proportional to ID/CSDownload SVG

Dimensions (inch)

Dash number	AS568-278
Inside diameter	11.984 ± 0.065
Cross-section	0.139 ± 0.004
Outside diameter (calculated)	12.262
Nominal	12 × 12 1/4 × 1/8

Dimensions (mm)

Inside diameter	304.39 ± 1.65
Cross-section	3.53 ± 0.10
Outside diameter (calc.)	311.45

Material options for -278

Viton / FKM Nitrile / Buna-N EPDM Silicone Fluorosilicone Neoprene

Check your groove for -278

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Groove depth (in)Groove width (in)Installed ID / rod (in)

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Same cross-section (0.139 in)

-274 9.984 -275 10.484 -276 10.984 -277 11.484 -278 11.984 -279 12.984 -280 13.984 -281 14.984 -282 15.955

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