COMPLETE FRIENDLY AFTER SALES SUPPORTIf you have any questions, please contact us through Amazon Supports, we will solve the problem for you within 24 hours, our goal is to provide you with a great workout experienceTHREE IN ONE METAL SPRING RESISTANCE SYSTEMCrafted with high-strength metal springs,this twister arm trainer ensures strong elasticity, durability,and stability, make sure long service life. More importantly,there is no jerking sensation in spring resistance, reducing joint impact,which provides a smooth,uninterrupted motion during your workout. Also featuring three adjustable intensitylevels(primary/intermediate/advanced),easily meet your diverse exercise needsEASY TO ASSEMBLE & PORTABLE WORKOUT ANYWHERECause the twister arm trainer is detachable design, it's simple to assemble and carry, so whether it's in the gym, office, or traveling, it won't delay the training process. It's the ideal fitness solution for busy lifestyles, helping you stay on track with your fitness routine wherever you go. Work at your own pace and enjoy a stress-free, efficient workout that's effective and convenient, it's a great addition to your gymEFFICIENT MULTI-FUNCTIONAL FULL-BODY WORKOUTThe Twister Arm Trainer as your personal workout trainer will help you get a killer chest workout! Its unique U-shape work multiple muscle groups with precision. Whether it's the biceps, triceps, deltoids, pectoralis major, or even leg muscles, etc, they can all receive effective stimulation and exercise, helping you shape a strong, and well-defined upper body. It will help build muscle and stamina over time!HIGH-QUALITY MATERIAL & ERGONOMIC COMFORT DESIGN Twister Arm Trainer is designed with your safety and comfort in mind, each spring workout bar is wrapped with a durable leather cover, which not only offers solid stability and reliable resistance, but also ensures a comfortable grip, preventing hand fatigue and discomfort during your workouts. Moreover, the thickened anti-slip foam extends the service life of the spring, avoids rust, and brings you a more reliable exercise experience