This Clark Sliding Door Opener Model 21000 is in real good condition and guaranteed to functions 100%. It came from a local MFG that was upgrading equipment and we can accept pay pal or your credit card. Please contact me with any questions. An electric operator for a sliding door mounted for sliding movement along a track, comprising a motor having an iron cooling flywheel disposed on a drive shaft thereof, the flywheel being provided for imparting a predetermined amount of inertia for starting and stopping of the motor such that the operation of the motor is characterized by a soft start and stop. A worm gear reducer is connected to the drive shaft for effecting a predetermined reduction ratio of rotation. A limit switch is coupled to the reducer for limiting rotation of the drive shaft to a predetermined number of rotations, and apparatus is provided for coupling rotation of the drive shaft to the linear movement of the sliding door along the track Track Page Views With Auctiva's FREE Counter