Knowing the moisture content of your lumber is critical. Testing the moisture content of walls and other surfaces during construction is equally important. This professional meter is simple to use with a dual-scale LCD readout, and it has built-in test features. Wood can be tested within a tolerance of 1 from 6 to 44. Building materials (wall board, sheet rock, cardboard, plaster, concrete and mortar) can be tested with an accuracy of 0.05 from 0.20 to 2.0. Weight 3-1/2 oz. Length 5". This is a very handy instrument.