Speedboosters are a popular option for adapting lenses to the BMPCC/Micro due to the camera's s16mm size sensor. While speedboosters are great, having two mounting points can cause problems with the safety of your gear by adding a possible point of failure when larger lenses are in place.
 
An example of this being if either the lens or speedbooster is not fully clicked into place. Handling the camera by the lens--or even turning the lens for focusing–can cause whichever mounting point to turn out and disconnect; risking either the lens or the camera to fall to the ground.
 
This adapter lock eliminates one of the possible points of failure by locking the speedbooster to the XLCS Cage itself via the 4mm threaded holes on the face of the cage. Simply replace the foot of the speedbooster with this lock and then fix it to the face of the cage. 
 
An added benefit is relieving the MFT mount on the BMPCC and Micro Camera from the additional strain that can be caused by the larger lenses that might be used with the speedbooster.
 
Machined from high-strength Aluminum; anodized black.
 
Verified to work with both Metabones and Viltrox speedboosters (the 2 most popular brands). The adapter lock will also work with many other basic adapters that have removable feet.