007 Silicone O-Ring, 70A Durometer, Red, 5/32" ID, 9/32" OD, 1/16" Width (Pack of 20), Replacement for EATC Temperature Controller, Free with Installation Tools: Amazon.com: Industrial & Scientific
Glorious sell 40A/70A O-Rings at both 1.5 and 2.5mm for $10. Thought I'd mention this as usually people only talk about WASD. (link in comments) : r/MechanicalKeyboards
O-Ring Kit, Plumber's-Pak AS568 Buna-N 70A Durometer, 200 Pieces, 12 S | Great Western Seal and Gasket