TnP Accessories 1" Standard Barbell is a solid steel bar with chrome palting, 2 spink lock collars and knurled grip sections. the 2 chrome-plated spin lock collars ensure the weight plates are held firmly in place, these 2 collars prevent the weight plates from sliding or falling of the barbell. Spin lock collars provide a quick release while still more that capable of holding weight plates in place. this is ideal for 1" “Standard” weight plates which have a 1" inner diameter hole