The all-new Amtech ErgoZM Magnifier has the established ErgoAm design with advanced feature to adjust working distances on each side within a range of 400 to 600mm while maintaining a wider field of view, which guarantees comfort while working. New Wireless LED light provides powerful and round focus white light, touchable power switch and brightness adjustment, easy one-handed operating. Total only 29.8 gram (light and battery), most comfortable user experience Three batteries provide energy for a day’s work. Headlight Weight: 10gm Brightness: 35,000 Lux Light Colour Temperature: 5800 Battery Type: Lithium Ion Weight: 20gm Recharge Time: 1.5 hr Run Time: 140 min. Prescription is for carrier lens and inside the loupe for working distance correction.