ROBUST MATERIALS: Optional outside diameter: 2PCS 30 mm (suitable for 27mm rod, 2PCS 28 mm (suitable for 25mm rod, 2PCS 25 mm (suitable for 23mm rod, 4PCS 30 mm (suitable for 27mm rod. The dumbbell clamps are made of high quality material, this barbell collar is robust and durable. The most suitable loading weight of the barbell clip is about 10 kg, preferably no more than 15 kg. If the weight is too heavy, the product can be easily damaged.SAFE DESIGN: Spring powered snap-latch design to keep you safe, faster than classic spring locks, more safety when exercising because the weight plates are firmly and securely fixed.EASY HANDLING: The dumbbell clamps are easy to use, one-click attach and remove, and snap-lock securing; its lightweight, easy to carry and store.GOOD PERFORMANCE: The sturdy cast body and the high-pressure grip pads inside make the brackets of our dumbbell clamps practically indestructible. The weight plates are suitable for most cast grip plates, cast plates and rubber grip plates.GREAT ACCESSORIES: They are perfect for crossfit training, strength training, weight lifting and any workout with standard dumbbells.