This CRL Commercial Medium-Duty Automatic Door Bottom is mechanically actuated. An internal carrier bar with a vinyl insert drops from a concealed cavity to form a tight seal between the base of the door and the threshold. It is ideal for use where carpeted interiors require the door bottom to retract when the door is opened. Supplied with a frame "actuator" protector plate, the door bottom is field reversible for either "hand" of door.

Actuation of the inner drop down bar only functions properly when this door bottom is installed on the door. Testing by hand before installation will only drop the back of the bar. Proper function only occurs when the back edge (near the hinge side) drops down onto the sill. Once the back of the bar makes contact, the front edge will drop, creating the seal. At this time, adjustments can be made to the threaded hex plunger by backing out the plunger to increase the seal pressure against the sill.