The kit includes the wearable parts that you should always have on hand. Older Fuji cups with the black-coloured lid can be converted to use the 2038 Plastic Diaphragm. If you haven't upgraded yet, we recommend you do so. We have found that by using this diaphragm in combination with the 2024 pressure tube/check valve, there is very little chance of paint backing up the pressure tube. To use the diaphragm, the older 2036 gaskets are too thick so they must be exchanged for the new 2037 Thin Gasket.