LuckySunDecorQZ 40oz tumbler lid which I received was missing a gasket because when I put the new lid it just easily came off and on. There was no gasket that prevented the lid to come off. Luckily I still had the original lid for my tumbler, I removed the black gasket (old lid) and put on the new lid, the fit was perfect. The lid was tight and fit perfectly and there was no leak. I took picture and the white gasket came with new lid. I put the black gasket (old lid) on lid. If there are other complaints of the new kid not fitting, this may be why.