Global O-Ring and Seal, LLC - What's square, round, and a superb seal at the same time? Square Rings! Square Rings fit in o-ring grooves and are interchangeable size-for-size. We keep Square
006 Buna-N O-Ring, 70A Durometer, Square, Black, 1/8" ID, 1/4" OD, 1/16" Width (Pack of 100): O Ring Seals: Amazon.com: Industrial & Scientific