The Barbell Collar is made of high-quality steel, durability, is not easy to damage to ensure your safe exercise. Durable material: the dumbbell spring collars are made of steel material, which is sturdy and durable enough, not easy to get rust or break, can provide you a firm support and grip for your barbell, help to hold bumpers in place. Functions: our locking collars clips are designed to protect plate weights from sliding off the bar, allowing you to exercise safely and confidently, very suitable for both men and women who love frequent fitness and training.About size: each barbell clamp is about 174 g in weight and the hole of each spring collar measures approx. 50 mm/ 2 inches in diameter, please measure your bar diameter of barbell before your choosing and ensure better fit. Suitable occasions: the dumbbell spring collars are suitable for home, gym and outdoor activities, can be applied for workouts, overhead press, weightlifting and more sports, easy for you to use, can be quick to slide into the place and off the bar.