This prism assembly allows the user to quickly adjust the tilting target from behind the prism as it is pointing at the instrument to allow accurate sighting. The targets are 6 x 9 inches. The prism can either be mounted in a 0 or -30 mm offset position. All come with a protective carry case for the target or complete system. This complete prism system comes with a 62 mm copper coated prism in a sealed canister.