Firstlaw Fitness I-Beam Rolling Punching Bag Mount - (Black - 3.5" - 7.0" Wide I-Beam) THE FIRSTLAW FITNESS I-BEAM ROLLING MOUNT IS PRESET TO FIT YOUR 5.5" WIDE I-BEAM THE I-BEAM ROLLING MOUNT SMOOTHLY ROLLS ALONG AN I-BEAM TO MAXIMIZE SPACE DUAL BRAKE SYSTEM HOLDS HEAVY BAG IN PLACE DURING WORKOUT - OR SUPERCHAGE YOUR CARDIO AND USE WITH BRAKES OFF DESIGNED FOR HEAVY BAGS UP TO 300 LBS - EASY TO INSTALL IN JUST MINUTES - ALL MOUNTING HARDWARE INCLUDED POWDER COATED FOR A LONG LASTING FINISH - 100% MADE IN THE USA!