Keep your plates locked in while you lift, then swap them out in seconds. These TwistLock® Pro Collars have a patented design that guarantees transitions between sets are smooth and efficient - a must during high-intensity workouts when every second counts. And say goodbye to struggling with hard-to-close barbell clamps and flimsy weight clips - these barbell collars fit snuggly on any Olympic barbell and provide the holding power you need during rigorous workouts. Lightweight but robust, these collars feature a heavy-duty aluminum build with medium volcano knurling for an easy grip. Equipped with strong magnets, they can be stored on a rack or stuck on an upright to free up your hands while you switch out your plates. Please Note: TwistLock Collars are designed for Olympic bars and will not fit 48mm axle sleeves found on some specialty bars and plate-loaded machines.