30mm Diameter | 10x magnification. 5mm diameter LED light. 30mm diameter integral 2x optical glass lens. Powered by 3x AAA batteries (not supplied). LED lasts around 40,000 hours under normal use. Battery life = 40/50 hours under continuous use. Compared to a conventional bulb the LED diode lives up to 1000 times longer with 90% less power consumption. Complete with plastic case with belt loop.