DEF Digital UL Meter, Engineered Polymer In Line Turbine Meter That May Be Installed At The End Of A Hose Or Plumbed In A Fixed Pipe Installation With The 1" NPT Inlet/Outlet, Use For DEF, Agriculture Chemicals, Non-Potable Water, & Many Other Chemical Applications, 20 Pre-Set Calibration Factors Based On Fluid Type Or Can Be Easily Calibrated In The Field, Uses 2 "AA" Batteries That Can Be Easily Changed When Needed, A Low Battery Level Alert Will Notify The User When It Is Time To Change The Batteries.