AMH2K-7X AQUA SHIELDTM Circulator for Outdoor installation. Installs on TANKLESS HEATER WITHOUT BUILT-IN PUMP ON DEDICATED RETURN LINES, For up to 100 Ft. of total pipe length and tankless minimum Flow Rate of .5 GPM or less: AM7-SUV1AXLT1 stainless single speed circulator with union connection, 10 ft. line cord, with outdoor enclosure, automatic built-in timer, built-in sensor/switch (115°-125°), water, sprinkler, bug, freeze protected, anti-tampering locking device tab. Union Kit UK75T 3/4″ threaded male fittings included. Patent pending.