Type: SDJ-02, SDJ-05, SDJ-10/20 Image: Erect Field of vies: 1°30 Magnification: 30X Clear objective aperture: 45mm Shortest focusing distance: 1.35m Resolving power: 3 Minimum reading: 1/5 Range of compensator: ±3 Accuracy of circular bubble: 8/2mm Accuracy of plate bubble:30/2mm Voltage: 6V Battery life: 15h