Power Twister Exercise Bar-Materials: High Quality Carbon Steel Springs and Non-Slip Plastic Handle.Strengthens the chest, back, shoulders, biceps and gripPerfect for building upper body strength.Suitable for people: young, adult, beginners”Net Weight”: 30kg class Arm length 59CM weight 1.3 kg40kg class arm length 61CM weight 1.5 kg50kg class arm length 64CM weight 1.8 kg60kg class arm length 64CM weight 1.9 kg”material”: Stainless steel Spring “arm”: 30KG 40 50 60 arm function: Exercise shoulder, arm and back muscles to make the body healthier and stronger method