AS568 O-Rings

In the US, the most common standard inch sizes of o-rings are per the AS568 specification and are commonly referred to as “AS568 O-Rings”. These AS568 Sizes are grouped by Cross Section, and then by Inside Diameter with “Dash Numbers” (e.g. AS568-225 calls out an o-ring with a .139” C/S and a 1.859” I.D.).

View our AS568 Size Chart for a full listing of all sizes and dimensions.

Global O-Ring offers the full line of AS568 Size O-Rings in the following materials:


Standard Materials Durometer Color Material Designation
Aflas® 80 Black A80
Buna-N (Nitrile, NBR) 50 / 70 / 90 Black/White N50
/ N70 /N90 /WN70
EPDM (peroxide-cured) 70 Black E70
Fluorosilicone 70 Blue F70
HSN (HNBR) 70 / 90 Green/Black HSN70
/ HNBR90
Neoprene® 70 Black C70
Polyurethane 70 / 90 Clear U70 / U90
PTFE (Teflon) 55-60 Shore D White TEF
PTFE Encapsulated Viton® 90-95 Clear/Black TEV
PTFE Encapsulated Silicone 85-90 Clear/Red TES
Silicone 70 Red/Rust S70
Viton® (FKM, Fluorocarbon) 75 / 90 Black/Brown V75
/ V90 /BV75


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