XHL Xenon Halogen Technology used. Durable and easy to clean. The handle is shared with other otoscope and Ophthalmoscope. 2×AA batteries used. 5 different apertures. Range of lenses: -20 D to +20 D + 1 2 3 4 6 8 10 15 20 - 1 2 3 4 6 8 10 15 20