This 4mm adapter plate allows you to add two Peak Design Anchors to your Capture Clip v3 allowing you to attach it to other accessories, e.g. Peak Design Slide strap. This solution is sleek and results in the ultimate strength because the anchors loop around each of the metal screw bosses. Peak Design says the Anchors are built to withstand over 200 lb (90 kg) of absolute force. 4mm is perfect thickness if you use the standard thumb-screws. You will need the 7mm version if you use the longer hex screws.