The Mopeka Check PRO Sensor for Water. The PRO Sensor combines all the best technology of our ultrasonic sensing for the best sensor performance ever. Water Tanks: All Gray and Potable water tanks; Any flat bottom plastic or metal water tank less than 48″ overall height. Mounting: Retaining collar (included) that sticks to tank bottom with pre-applied permanent adhesive. All preparation materials included. How to read level via Bluetooth: Free Mopeka Check APP on your smartphone or tablet. Power: CR2032 Battery. Also compatible with Mopeka Wifi Bridge, allowing remote reading of sensor using APP. This package includes 1 Pro sensor, collar set with preinstalled adhesive, and adhesive prep materials.