O-Ring, Black Nitrile Buna-n, 0.071" ID x 0.063" CS/Width, (Large #4)(50 Pack): Amazon.com: Tools & Home Improvement
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RFS Carbon Steel 4 Bolt O-Ring Side Square Flange, 1” Socket Weld, Working Pressure up to 210 kg/cm², Weld-in SSA Flange for Connection Between Pipe & Fittings, JIS F7806 Standard: Amazon.com: Industrial