Minimize the noise, jarring and vibration when working out on your heavy bag. We have engineered an improvement to the traditional spring and swivel: the Heavy Hanging System™(H2S™). Its patented design decreases excessive bouncing that can cause damaging stress to both the bag and the hardware. All Balazs mounts, including those for the UBS, feature the patented H2S™. The standard H2S™ holds bags up to 150 pounds. A spring upgrade is required to hang bags over 150 pounds.