This site offers instructions and diagrams to help you build your own cavaletti. What is a cavaletti, you ask?
Whether you show English or Western or just train for fun, cavaletti can be a valuable training tool. The cavaletti is simply a pole set on 2 x's that give you three (3) training heights: 7", 12" and 17" for gymnastics.
Four cavaletti set in a line at the lowest level can improve a horse's trot; set at the highest height they can make a small bounce jump. Cavaletti can be an integral part of your training equipment.
TEXAS HORSEMAN'S DIRECTORY - How to build cavaletti