Overmoulded housing protects unit and maintains calibration under jobsite conditions. 2-button operation and low battery indicator. Includes 3 x AA batteries giving 20+ hours runtime. Specifications: Laser class: 2, 1mW. Accuracy: 0.3mm/m. Number of beams: 2. Direction of beams: vertical/horizontal. Indoor visibility range: 15m. Self-levelling range: ±4°. Power supply: 3 x 4.5V AA batteries. Tripod connection: ?".