The rack-mounted Dumbbell Weight Bar Holders allow you to place one pair of dumbbells on either side of your X-3 or TITAN Series Uprights in order to conveniently and safely perform free-motion dumbbell lifts. Designed with a J-hook style mounting system that allows you to install the bars to your rack within seconds. Easily clip the mounting system into the uprights by inserting the pin and rotating the holders down. No hardware required. The safety spotters can hold up to a combined 450-pounds and are a great asset when transitioning between sets and exercises. Lock them to your desired height and get to lifting!