ZERO FUNCTION AND LEVEL FUNCTION -- inclinometer or tilt gauge to set or check relative angles between surfaces(You can hit the on switch to set the current angle of zero and them measure the total stroke of the angle finder.), also works as true digital level for tight spots. LARGE LCD BACKLIGHT - EASY TO READ -- large, bright display stays on as long as you’re using it, improving visibility and usability STRONG MAGNETIC BASE - Magnetic base easily attaches to saw tables, fences, blades and other metallic surfaces; INVERTED USE: Display automatically rotates to read the correct way up, works in the horizontal and vertical planes. HIGH ACCURACY AND FOUR MEASUREMENT MODES- Use as mini digital protractor, displays bevels in degrees, IN/FT, mm/M, percent slope.It provides precise measurements, whose accuracy is ±0.1° at 0 and 90 degree, ±0.2° at any other angles CERTIFIED IP54 dust and water resistant and AUTOMATIC POWER OFF - Powered on by 2 x LR03 AAA Battery and automatically turn off after 3 minutes without operation, Low battery indicator on the Screen. PLEASE NOTE: If you switch on the level box and received an “Err” message this is caused by the level box either being held in your hand and tilted too far back or to much in front or lie flat on its back once straightened up by placing it on a surface Err disappear this is by design. Bonus Batteries Included: Supplied with 2 extra AAA batteries so you're powered for longer straight out of the box. Versatile & Durable Tool: Ideal for carpentry, welding, construction, and DIY tasks. Backed by UK support and 12-month warranty., Manufacturer: ULTRATOOL