Made of durable aluminum alloy and LED, pocket clip design, easy to carry. Pupil gauge and 5 cm ruler printed on it, adds convenience. White and orange light are available. Powered by 2 AAA day batteries, product not including batteries.This reusable LED penlight is push button to click on and off instead of holding the clip down to keep the light stay on throughout the entire use, which makes use way more efficient and simply. It can be used as lighting mini flashlight, but it is more suitable for medical!