Where ever they sell o rings! I would try to stick with 70 Durometer hardness, IMHO only because I was given the Amazon link by ProVape CS and I used one to replace Jackie's last June and it's working just fine.
https://www.amazon.com/004-Buna-N-O...id=1433362692&sr=1-1&keywords=o+rings+5/64+ID
FDA SILICONE O-RINGS 004 QTY 75 5/64" ID X 13/64" OD | eBay
