Watts 1/2 in. D X 1/2 in. D Brass Double Check Valve 9-98-998-41 which allows time to exit

which allows time to exit a room or to get into bed before the lights turn off

crank handle

fit your dryer duct with an Imperial 4-in dryer connector elbow

Brand Name: BK Products

Watts 1/2 in. D X 1/2 in. D Brass Double Check Valve 9-98-998-41 which allows time to exitDual Check Valves with Intermediate Atmospheric Vent prevent the reverse flow of hot or cold polluted water from entering into the potable water supply. It consists of a brass body with stainless steel internal parts, integral strainer and two durable, tight sealing, rubber check valves. Designed for continuous pressure, non health hazard applications in smaller supply lines, such as laboratory equipment, processing tanks, sterilizers, dairy equipment