1. Arm swing mechanism: with our volleyball spike training equipment you can easily improve your jumping, ball speed and power, arm swing technique, foot work and contact with the ball 2.No more tangles: Unlike other products on the market that have tangles between the bag rope and the basketball frame, we solve them by adding an inflatable ball inside your basketball frame 3. Adjustable length: our volleyball spike trainer is easy to adjust, you can adjust the rope from 38.1 cm to 76.2 cm in length according to your height. 4. Safe design: Our spike training equipment is designed not to involve any metal or hard objects close to where your hands come into contact with the ball, making it completely safe to practice with our equipment. 5. Improved reaction: The reaction ball is designed to bounce randomly so volleyball players can enhance their hand-eye coordination, improve their reactions and generate fast reactions