The Rokinon XEEN Support Mount Kit for Canon allows a user to swap the lens mount of their Rokinon Xeen prime lens at will. Between Arri PL, Nikon F, Canon EF, and Sony E. There's no limit to the range of cameras you can use the Rokinon Xeen primes on. Installation is simple and straight forward requiring only some basic tools. Collimation should still be taken into consideration when swapping mounts in order to maintain proper focus accuracy.