Amazon.com: uxcell Nitrile Rubber O-Rings 30mm OD 26mm ID 2mm Width, Metric Buna-N Sealing Gasket, Pack of 50 : Industrial & Scientific
uxcell Fluorine Rubber O-Rings, 30mm OD 22mm ID 4mm Width FKM Seal Gasket for Machinery Plumbing, Green, Pack of 5: Amazon.com: Industrial & Scientific