Here's the premise of how it works.

This adapter will put your lens' rear element right at the 44mm flange distance it should be, but this comes at the cost of 1mm of zoom on the wide end of the lens. The rear element moves backward as the lens zooms out, we've added a stop to this adapter to prevent it from moving far enough back to hit the mirror. 

If you are using the lens on an EF to RF adapter you can remove the stop to get the full 24mm wide view.

Putting this adapter on the lens is easy. Just remove four screws on the back of the lens. Use some plyers to break off the aluminum tabs used to meter couple the lens to an slr camera (as shown in the pictures). Then screw on the adapter back plate. And you are done! The infinity focus should be good to go!

De-clicking this lens can be tricky due to internal springs on the aperture blades. We've added bend out flaps to this adapter which can enable you to de-click the lens as well!

This kit will come with two adapters incase one should ever break on you. These are adapters are very strong, but they are made from plastic and so a second adapter is included incase you should ever have any issues such as dropping the lens while it's mounted to a camera.