Volleyball Spike Trainer VST-100 Sturdy, portable plastic base - Can be secured with weight, sand, or water for stability. Provides the optimum platform for practicing Volleyball footwork and hits from any spot on the court. 36 volleyball hit height adjustment - Designed to simulate junior, womens and mens hitting height. Easily adjustable between 7 1/2 ft and 10 1/2 ft Simple Assembly - Designed just like a portable basketball system, the Volleyball Spike Trainer can be assembled quickly and with minimal tools Sturdy, integrated elastic ball assembly - Dual-band elastic ball assembly provides the perfect set every time for realistic hitting practice in the gym or the privacy of your home Large wheels on base - Easy movement of Spike trainer to Gym equipment storage room or safe, out of the way location at your home