DoorKing Maximum Security operators are designed to operate vehicular slide gates in limited (Class III) and restricted (Class IV) applications only. These operators should never be used in applications serving the general public. These operators are designed so that they can easily be mounted in the front, center or rear of the gate without any costly and time consuming field modifications. Center mounting the operator requires an optional pedestal mounting base. The speed control on the 9220 and 9230 models allows the user to set the speed of the gate from 1/2 to 2 feet/sec., and provides slow-start and slow-stop functions as well.