Different sizes: Available in three sizes to fit weight discs with diameters of 25 mm, 28 mm, and 30 mm. Refer to the product images and details page to measure and select the correct size. If uncertain about the proper clamp size, contact the seller for assistance. High-quality materials: Designed for durability and safety. Constructed from high-quality spring steel for strength and reliability, with plastic handles that are smooth, durable, and easy to grip. The combination ensures a secure hold during workouts. Exercise safely: Dumbbell collars securely hold weight plates in place, ideal for weightlifting, strength training, and use with dumbbells, barbells, squat machines, and other gym equipment. A must-have for athletes, fitness enthusiasts, and bodybuilders. Easy to use: Features a firm grip and comfortable plastic handle for quick and simple installation and removal. Simply attach the clamp to the equipment and tighten securely. Wide range of applications: Suitable for both smooth and textured bars. Helps securely fasten weights during gym workouts, weight training, and bodybuilding exercises. Material: Plastic and stainless steel 2.5 cm model: Inner diameter 2.5 cm, length 8 cm, fits rods between 2.5–2.6 cm 2.8 cm model: Inner diameter 2.8 cm, length 8.5 cm, fits rods between 2.8–2.9 cm 3.0 cm model: Inner diameter 3.0 cm, length 8.5 cm, fits rods between 2.9–3.0 cm