The dumbbell set includes two handles, four 0.5kg plates, four 1.25kg plates, four 2.5kg plates, 4 collars, and a extended bar. Strictly selected materials, free of phthalate and lead. Unique rubber O-ring anti-loose design Free connection steel tube to change dumbbell to barbell. Give you more functions to build up muscle. With the steel connection tube, you can add more weight plates from 4kg to 33kg (includes bar weight) Ergonomic designed knurled handle grip makes your hands more comfortable. 143mm wide hand grip part give more room for your hand to grip, making it easier to lift without bumping your wrists for doing certain exercises.