Mopeka Pro Check Universal Sensor for Gas and Water TanksUniversal tank sensor for aluminum, plastic and poly tanks Uses ultrasonic technology to measure propane levels accurately Connects to app for real time mobile monitoring With its easy magnetic mounting, that avoids the need to mount permanently, the Mopeka Pro Check Universal Sensor is the perfect solution to check your tank levels while out in your RV, relaxing at your campsite or just enjoying a summer BBQ 99. 5% Accuracy Long lasting battery