uxcell Silicone O-Rings, 4mm OD 1mm ID 1.5mm Width VMQ Seal Gasket for Compressor Valves Pipe Repair, White, Pack of 30: Amazon.com: Industrial & Scientific
4mm ID x 6mm OD x 1mm thick O-ring. Buna-70. Quan 5. | eBay
uxcell Fluorine Rubber O Rings, 4mm OD, 2mm Inner Diameter, 1mm Width, Seal Gasket Black 50Pcs: Amazon.com: Industrial & Scientific
25.4x1 Oring 25.4mm Id X 1mm Cs Nbr Nitrile O Ring O-ring Sealing Rubber - Oil Seals & Other Seals - AliExpress