The nice thing with the felt clunk is that it will get ALL the fuel out of the tank.

The only down side is... the Walbro clunk that will fit in the Dubro tank isn't very big. I don't know if I would use it on anything bigger than a 20lb engine.

FYI... I use them, with a 2 or 4 oz tank, and make my own bubble tank for about $10. AND... it's Walbro P/N 125-527-1