The Scorpion 30mm Cross Mount is made from strong aluminum alloy and finished in a durable and attractive black Electro-Coat finish. The mount comes packaged with four 3mm machine screws to attach it to the back of your motor. The mount weighs only 3.8 grams by itself, and with the 4 screws, it weighs 4.7 grams. The hole spacing on the back of the mount where the motor attaches measures 25mm center to center in both directions.