The HC660 HydroClean Toilet Fill Valve solves the two biggest reasons for water loss in toilets; miscalibration and leaks. It easily calibrates to adjust the exact amount of water needed in the tank, refills quickly and jets clean the tank. A unique feature is the leak detection and signals when a leak is found. It is designed to fit most standard toilets and the height can be adjusted from 11 in. to 13.8 in. The HC660 installs easily without tools.