This device is used for turning your smoke ON/OFF while plane is in the air. Features: Rugged molded nylon with brass valving. Simple lever action for ON/OFF operation. Includes: One complete smoke valve. Also includes 2:2-56 nuts, 2:2-56 x 7/8" and 4: #2 washers. All hardware is used for mounting. Specs: 3/4" long, 1/2" high and 7/16" wide. The actuation lever is on the high side. Has two sets of mounting hole on both the long and wide sides. Inlet and outlet are on the longest ends. Requires: Servo for operation (and linkage), PERG7022, the pump for moving the smoke fluid, medium fuel tubing, a muffler that will accept a smoke system and installation of all components.Conley PrecisionPart PERVP-RSV-04