This pass-thru protector has a channel that will receive a flat-style 3-conductor extension cord (Woods Tri-Way Cord, $10.50 at Target). This allows the cord to pass through the doorway without the danger of getting pinched between the door and the doorjamb.Download stl file and print. Insert cord into the channel. The "inside" channel has a little bit more of an angle to help route the cable away from the door when it is fully opened.Place it in the door way. You may optionally use double-sided tape to secure the protector to the floor, but I've found that it's fine without.TurboCAD TCW file provided for reference.