USA Industrials - O-Ring: 55 mm ID x 61 mm OD, 3 mm Thick, Viton - 47406483 - MSC Industrial Supply
Amazon.com: YINGJUN CS2.5mm EPDM O Ring ID 52/53/55/56/57/58/60/62/63x2.5 mm O-Ring Gasket Seal Exhaust Mount Rubber Insulator Grommet 30PCS ORING Ring Gasket (Size : ID64x2.5mm) : Industrial & Scientific
Metric Buna O-rings 55 x 4mm Minimum 5 pcs - OringsandMore
Silicone O-rings 55 x 3mm Minimum 2 pcs - OringsandMore