UTG PRO M-LOK Made in USA Standard QD Sling Swivel Adaptor Precision Machined from 6061-T6 Aircraft Grade Aluminum for Best Corrosion and Wear Resistance Lightweight, Low Profile Design Uses the Least Amount of Space M-LOK Requires While Retaining Optimum Mounting Performance Adaptor Bidirectionally Mounts and Efficiently Utilizes Rail Real Estate by Mounting Either In One Slot or in Between Adjacent Slots On the Same Track Accepts Any Quick Detach Sling Swivel with 0.37" Diameter Swivel Stud QD Swivel Housing Designed with Quarter-turn Rotational Over Travel Stops to Restrict Swivel Movement and Prevent Sling from Unwittingly Getting Tangled Includes M-LOK T-Nuts, Screws, and Assembly Tool for Simple and Friendly Installation, No Gunsmith Required