Railz mount is machined from 6061 grade aluminum. Shell holder is crafted from lightweight poly_mer. Built for use with Mossberg 500, 590, and Shockwave Series Shutgun models; Not intended for use with other SHUTGUN models INSTALLATION: Unit installs into the factory mounting holes of Mossberg 500 / 590 / and 590 Shockwave Series shutgun models with no additional gunsmithing required Railz mount allows for the mounting of Picatinny or Weaver standard scopes, red dots, or other optics