Installation instructions are provided with the packaged part. Installation hole sizes and tolerances are given in the DME Mold Components Catalog as well. Use a plastic or rubber hammer when installing the Air Poppet into the installation hole, do not use a metal hammer. Do not strike the front, flat face of the valve. Do not modify the front, flat face of the valve in any way, as this can affect the final operation of the Air Poppet valve. Maintain a close tolerance press fit as shown in the DME Mold Components Catalog. Too loose of a fit could allow the Air Poppet Valve to move out of position, while too tight of a press fit could interfere with the movement of the valve. Additional warnings and instructions are given in the DME Mold Components Catalog as well as with the instructions provided with the packaged product.