This is the alert system that sounds an alarm when a dryer vent is blocked with lint. Excess lint poses a dual threat for homeowners: It¿s a fire hazard (15,000 clothes dryer fires a year according to the Consumer Products Safety Commission) and it forces the dryer to expend more energy to completely dry clothes. Because simply cleaning the lint trap is not generally enough to keep vents clear, this system detects the increased air pressure symptomatic of a clogged vent. The sensor probe, easily installed by hand into the dryer transition hose (the flexible hose that runs from the back of the dryer to the vent), monitors the dryer's efficiency and calculates the amount of blockage that builds over time. Five LEDs on the base unit indicate blockage amounts, and if lint build-up reaches critical levels, a 90 dB alarm sounds continuously until a reset button is pressed. Base unit includes a pass-through plug that frees up the outlet for another device. 31/2" H x 31/2" W x 1" D (1 lb.)