I just bought new petcocks for the R100, and they came with new mesh filters that go over the tubes in the tank. The mesh has aluminum "washer-like" structure at the bottom of it to which the mesh is attached-I guess the theory is it is soft enough to conform and seal to the bottom of the threaded tank outlets without a washer - no washers came with the petcocks, which I bought as complete kits. So, I'm crossing my fingers and will find out in about a week...