The minimum value maintenance symbol is a material moisture tester that uses resistance type measurement to measure the humidity of wood or building materials Maximum measurement Auto power off Low battery indication Pen-type design,compact and easy to carry. Battery type:2x1.5V AAA battery(ship without battery) Material Comparison Table: Material 1: The weight ratio of beech,,larch,cherry,walnut:8.5-60% Material 2: The weight ratio of oak,pine,maple,ash, ,and eucalyptus:6.8-53.4% Material 3: The weight ratio of cement mortar layer to concrete:0.9-24.5% Material 4: The weight ratio of anhydrous gypsum mortar layer:0.0-12.2% Material 5: The weight ratio of cement mortar:0.7-9.2% Material 6: The weight ratio of mortar to gypsum:0.5-11.0% Material 7: The weight ratio of bricks:0.0-17.8% Color: Red & Black Material: plastic Package Contents: 1 x moisture detector 1 x screwdriver (random color, no specified color accepted) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.