Never run out of LP fuel unexpectedly. The Mopeka LP TankCheck Bluetooth Sensor accurately measures how much fuel you have left. The LP TankCheck is an electronic device that very accurately measures the amount of LP gas contained in most LP cylinders/bottles and communicates that information wirelessly to any smart device with Bluetooth compatibility. This allows you to be aware of how much fuel is available at all times, simply by checking your smart device. Must download free APP for use.• APP can read up to 12 sensors at the same time• Sensor operates on included watch-type batteries• Feet pads assist in mounting sensor to bottom of tank• Includes one sensor and three feet pads Sensor operates on included watch-type batteries Includes one sensor & three feet pads for mounting to bottom of tank | AP Products Mopeka LP TankCheck Single Bluetooth Sensor