The Photon II Micro-Light is approximately the size and weight of a U.S. quarter. Has sliding on/off switch and momentary squeeze button. Has turquoise ("night-vision green") LED beam. At reduced brightness levels (try swapping a single CR2032 battery for the included pair of CR2016 batteries), the blue-green color of the turquoise is an excellent alternative to red for night vision preservation. Features quick-release key ring and a replaceable lithium battery.