FloodStop is a leading manufacturer of water shut off valves, leak sensors and leak protection systems that can help prevent costly damage to your property. This model is for 3/4" pipes and installs using a NPT pipe thread connection. Water heaters are under constant pressure and rust from the inside out so you don't know there's a problem until it's too late. And when they go, they release a huge amount of water very quickly and often the leak goes undetected for some time as they tend to be installed in remote areas. As soon as the FloodStop sensor(s) detect a small amount of water, the FloodStop will automatically close the water valve and sound an alarm. This is much better than traditional water sensors that simply make noise. With the FloodStop the source of damage (water) will be immediately dealt with. The Floodstop auto water shut-off runs on AC power with battery backup by 4 AA batteries (not included). * Additionally, there is a 'normally open' connection on the FloodStop controller, that can be connected to an alarm panel, automation system or an auto-dialer to trigger additional events or to automatically turn off pumps or appliances when a leak is detected.