I too know the joy of the melted plastic cap.GuyMcBeerdrinker said:you gotta go wide mouth. they are far easier to clean as well. I've owned several nalgenes for years (since '96). they are indestructable. only had two ugly run-ins with the bottom rack in the dishware where the cap was mangled, but you can buy replacement ones and pop them in. the bottle is made out of lexan...which is the same material as jet fighter canopies and (this is for todd) nascar windshields. like todd said they sell adapters (clicky)