I am usually satisfied with Andy Mark parts, but after using this gearbox in competition this year, and after hearing other horror stories from fellow FRC teams, I would highly recommend not buying this product. The Wormbox is made of nylon and aluminum. Lightweight - yes. However, this product is made of such non-substantial materials that it really should not be used to provide even modest torque to a robotic part. This year we replaced the nylon gear THREE times in two competitions, as the tension pins that transmit torque to the shaft tore right through the weak plastic. What's more, there is plenty of play in the Wormbox, and it should never be used on a part that needs to be rotated to a precise angle. Finally, this lightweight gearbox is a surprising $120.00. This is simply outrageous, considering the cheap material composition and relatively simple design. Overall, the Wormbox is incredibly unreliable for most robotics applications, and is handsomely overpriced.