An attachment for your weapon with RIS 22mm (or Picatinny, or whatever) rail. 40mm raise, length 75mm. Requires two M4x16 screws+washer+nut.
The weapon on the pictures is Delta Armory M4A1, and AIRSOFT, not a real gun.
40mm_rail_riser_75mm_long_v3.stl | 6.7KB |