Description: Premium carbon steel spring makes it have stronger tension. This twister bar can help exercise deltoid, pectoralis major, biceps, dorsal muscles and abdominals. It is durable to use because it has anti-rust and anti-deformation features. What makes you choose as you need is the various power choices design. Made of high quality carbon steel material, it is durable. We have various styles for you to choose. It is suitable for beginners, teenagers, chest exerciser, arm builder and so on. Item Name: Arm Power Twister Material: Carbon Steel Color: Black Strength: 20kg, 30kg, 40kg, 50kg, 60kg Features: Strong Tension, Comfortable Grip, Flexible Size Details: 20Kg Length: 54cm/21.26", Diameter: 3.2cm/1.26" (Approx.) 30Kg Length: 58cm/22.83", Diameter: 3.5cm/1.38" (Approx.) 40Kg Length: 60cm/23.62", Diameter: 3.7cm/1.46" (Approx.) 50Kg Length: 60cm/23.62", Diameter: 4cm/1.57" (Approx.) 60Kg Length: 61cm/24.02", Diameter: 4cm/1.57" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Arm Power Twister