Abstract: An apparatus for installing and removing a teat cup liner (or “inflation”) from a shell has a fixture which holds and retains the shell in position. A pair of shoes is capable of moving to engage a portion of the liner projecting from the shell to pull the liner downwardly. In an installation mode, the liner is pulled so that a sealing ring on the liner moves through a restricted opening into a sealing relationship with the shell at one end. The resiliency of the liner also causes a seal to be formed at the other end of the shell. In a removal mode, the liner is stretched by movement of the shoes in the same way as installation. A cutter of the apparatus is then activated to sever an end portion of the liner, including the sealing ring from the remainder of the liner, releasing the liner from the shell.