1, Roll up door openers 2, 24V DC motor drive unit 3, Rolling code technology 4, Safety auto-Reverse 5, ... selectable2, Motor Type : 24V DC motor , Quiet operation and reliability, Drive unit housed within the roll ,hardwearing #66 nylon gear mechanism no ... control. Push button on control box12, Safety : Safety Reversing The drive unit automatically,reverses should the downward movement of the door be ...