The unit comes with a 3 prong plug which the directions do not tell you where to install. The plug needs to be installed behind the chimney but the vent hose is in the way. Also unless my unit is broke, the fan speed sounds the same on all speeds. It say’s to use bumpers that are attached to to unit but if you use them the unit doesn’t sit flush with wall and the chimney doesn’t fit flush as well. Overall I wouldn’t recommend this product