SpecificationLight source: 5mw semiconductor laserWavelength: Line: 635nmLinear accuracy: ± 2.5 / 5MBrake way: Reluctance movingWidth: <2.5mm / 5MTemperature: -5 ℃ ~ 45 ℃Working life: more than 2000 hoursSize: 98 * 92 * 128mmBattery: 2 AA batteries（Not included)Alarm: buzzer long ringAK435 at horizontal and vertical lines Crossed point adding a highlight. This increased highlights suited for brighter construction site. Even in outdoors， increased highlights were visible. Use 2 Line 1 Point principles， can draw Horizontal line， easy to use.Function Description:1. According to positive and negative direction mounted two batteries， turn right switch knob is turned on， all laser line all bright.2. Increased highlights and wall mount design， portable and practical， long-distance also can visible.Package included:1 x AK435 360 degree Self-leveling Cross Laser Level meter