From the manufacturer:
The Secure Quick Release (SQR) is an attachment system designed to quickly remove gear from one location and attach it to a different location. The two piece connection system allows the user to attach multiple platforms to their belt, drop leg, chest rig or other surface to quickly take their holster or magazine and move it around depending on what the situation requires.
BASE PLATE ONLY – This part attaches to your belt, drop leg, chest rig or other surface. Screws and backing nuts included.