2 Sizes: The package contains 6 pieces of dumbbell collars, including 4 spring lock collars with a 25 mm (0.984 inch) inner diameter for smooth barbell bars and 2 dumbbell collars with a 24 mm (0.945 inch) inner diameter for threaded dumbbells. Different sizes are suitable for different dumbbells. Please check the size and type of your barbell carefully before purchasing. Quality Material: The spring clip collars are made of high-quality steel to ensure durability and reliability. They are rust-resistant and sturdy, not easily broken or deformed, and designed to last. Easy to Hold: Each spring clip features a smooth handle for easy gripping. The design allows for quick and convenient attachment and removal from the barbell, reducing effort and improving usability. Safe Training: These barbell collars can withstand heavy loads and intense movement, making them ideal for weightlifting and strength training. Suitable for both home and fitness use, they help keep weight plates secure during fast or powerful exercises, reducing the risk of weights shifting or falling. Easy to Handle: The spring collars allow for quick changes between weight plates. They securely hold dumbbells in place during lifting, and can be easily loosened and tightened, allowing smooth adjustment when changing weights.