This air cartridge has become quite good and fits exactly on the Schrader valve; Initially the internal silicone made it difficult to push the chuck locking lever, but after a few uses I noticed that the silicone sleeve was too long (by 1mm) and was being pushed out of the chuck making it very hard/difficult to push the chuck lever . After a few uses the slightly extra silicone has actually come loose and is fairly smooth to use, locking securely onto the Schrader valve and easy to remove once the lever is unlocked.