2 Sizes: The package contains 6 pieces of dumbbell collars, including 4 spring lock collars with a 25 mm inner diameter for smooth barbell bars and 2 dumbbell collars with a 24 mm inner diameter for threaded dumbbells. Different sizes are suitable for different dumbbells. Please check the size and type of your barbell 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 collars are simple to attach and remove from the barbell, saving effort and allowing for quick application. 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 gym use, they help keep plates secure during fast or powerful workouts, reducing the risk of weights shifting or falling. Easy to Handle: The spring collars allow quick and easy weight changes. They securely hold weight plates in place during lifting, and can be fastened or loosened rapidly, allowing smooth adjustment when changing weights.