ST stands for Smooth Touring and that's what you get with our updated bracket. We overmold our custom plastic blend over and through the holes in the aluminum base, forming bushings that last four times longer than their previous brass version. Weight: 3.28 oz/pr (93g) In The Kit: 2 x ST Brackets 6 x Bracket Screws Compatibility: ST Brackets are compatible with all Spark R&D Tesla, Tesla T1, Burton Hitchhiker bindings, & Nitro Vertical binding. The bracket is not compatible with Spark R&D Pin Mount bindings.