1Pc Silver Dumbbell Spring Collars Barbell Clamps Locking Collars Clips for Weightlifting Exercise Fitness Training Supplies Exercise Collars (2 Inch). These locking collar clips will fit any standard 2 inch (50mm) diameter barbell or dumbbell. These spring collars are perfect for weightlifters, bodybuilders, powerlifters, and fitness enthusiasts who want to add variety and challenge to their workouts. With these spring collars, you can quickly and easily change the weight on your barbell, allowing you to customize your workout and target different muscle groups. The locking mechanism keeps the weights securely in place, preventing them from slipping or moving during exercise. Whether you're working on your bench press, squats, or any other exercise, these spring collars will provide the stability and support you need to perform at your best.