Yes they are a common item at any hardware store...More than likely in whatever section they carry rubber washers. Take the lid and airlock with you to verify a snug fit.
I'm thinking that the sizes are 7/16 inch inside hole diameter, with a 1/2 inch outside groove diameter, but I can't remember....
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Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman
I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew