HEAVY DUTY METAL MATERIAL. Engineered with fast-grip knurled handle make from ultra strong NEVER RUST aluminum. TARGET YOUR HANDS,WRIST AND FOREARM DIRECTLY.BUILDING CRUSHING GRIP STRENGTH. For powerful, stronger gripping and forearm strength.DIRECT CARRY-OVER BENEFITS. Weightlifting, Powerlifting, Bodybuilding,Gymnastics, Rock climbing and overall health fitness.BRING IT WHERE EVER YOU GO. Squeeze out a few sets any time any where.