500pcs 0.8mm 31mm-40mm O Ring Rubber Seal Washers Waterproof Round Watch Gaskets - Repair Tools & Kits - AliExpress
uxcell Nitrile Rubber O-Rings 40mm OD 36mm ID 2mm Width, Metric Sealing Gasket, Pack of 10: Amazon.com: Industrial & Scientific
40X2.75 Oring 40mm ID X 2.75mm CS NBR Nitrile O ring O ring Sealing Rubber|Seals| - AliExpress
uxcell Nitrile Rubber O-Rings 47mm OD 40mm ID 3.5mm Width, Metric Nitrile Rubber Sealing Gasket for Automotive Machine Plumbing, Pack of 5: Amazon.com: Industrial & Scientific
5pcs/lot Fluorine Rubber Ring Black Fkm Oring Seal Cs:2.4mm Od31/32/33/34/35/36/37/38/39/40mm Rubber O-ring Seal Oil Ring Gasket - Gaskets - AliExpress
High Temperature Silicone Rubber O-ring (1 pair) for 40 - 42 mm Dia Alumina or Quartz Tube - EQ-SOR-40