Upgrade Your Power Rack: Enhance your strength training experience with these bottom reinforced J-hooks from Kipika Fit. These hooks are designed to fit 3"x3" steel tube power racks with 5/8" or 1" hole, so you dont need to buy two different sizes to fit your equipment. Please measure your power rack size before buying Easy Installation: Installation and removal of the round tube sleeve can fits in 5/8" or 1" holes of the power cages. Insert 5/8or 1 bar into power racks 5/8 inch or 1-inch hole, and swing down to lock in place. No tools required