The Vertical Challenger by Tandem accurately measures vertical jump and reach. The unit telescopes to accurately measure height from 4 to 12 feet. Whether you coach volleyball, basketball, football, or other sports, the Vertical Challenger is easy to use. You will be able to track vertical jumping ability over time allowing you to assess your training methods. Movable arms are placed at 1" increments for accurate measurements. The heavy duty base is fitted with easy-glide casters for easy portability.