stylish hardened alloy picatinny rail fits Mark III, Mark IV and 22/45 Allows the fitting of dot sight or scope. Rail fits pistols with factory pre-drilled receivers. Can be mounted two ways (see pics) forward of rear sight or without rear sight. Mount has 4 holes, only 3 will be used at any time. Includes 3 screws Can be mounted two ways (see pics) forward of rear sight or without rear sight. Mount has 4 holes, only 3 will be used at any time. Two colour options. 1) Black 2) Silver NOTE: Does not fit Mark I or Mark II pistols + I have 222 Loctite listed and its recommended to use on the screws.