probably a killer deal for $11.00, but crazy. about 3 bucks each with shipping. It's a part that might cost under .10Cents each to manufacture. Being a bit more hillbillyish I get oring just slightly undersized od, add a trace of contact cement on the corners of the bowl and lay them flat on a piece of glass so I can see it, clamped over night it'll learn a set to buy you some installation time. I think the orings are available at a bearing store in a package that cost 1.00 and some change. get the fuel resistant kind. and if you take them apart in the future, an oring might start to pop out of its recess, dry it and add some contact or neoprene glue at the corners again very lightly, and it stay's in place to assemble. contact cement is getting expensive. Neoprene glue for wetsuits is still pretty cheap. nobody will ever know.