SmallRig 17mm Threaded Lens Back Mount Plate for iPhone 15 Pro Max / 15 Pro Cage 4394, locked by a screw and a slot, can be connected to a 17mm threaded lens. It is interchangeable with the M-mount backplate of the original cage and precisely hollowed to fit the iPhone ultra-wide-angle lens perfectly. SmallRig 17mm Threaded Lens Back Mount Plate for iPhone 15 Pro Max / 15 Pro Cage 4394, locked by a screw and a slot, can be connected to a 17mm threaded lens. It is interchangeable with the M-mount backplate of the original cage and precisely hollowed to fit the iPhone ultra-wide-angle lens perfectly.