28mm x 34mm x 3mm O-Ring (5 pieces): Amazon.com: Industrial & Scientific
uxcell Nitrile Rubber O-Rings 7mm OD 3mm ID 2mm Width, Metric Sealing Gasket, Pack of 200: Amazon.com: Industrial & Scientific
Othmro 50pcs Nitrile Rubber O-Rings, 3mm Wire Dia 12mm OD Metric Sealing Nitrile NBR Rubber Washers for Oil or Air Sealing, Professional Plumbing, Car Repair, Air or Gas Connections Black: Amazon.com: Industrial
20mm x 26mm x 3mm O-Ring (5 pieces): Amazon.com: Industrial & Scientific