2 5/8 inch overall. Color cylindrical housing. LED lighting source is viewable from 360 degree. High impact resistant design. Waterproof to 11, 500ft. Twist on/off tailcap switch. Working temperature: 14 DegreeF to 176 DegreeF. Battery life: up to 30 hours. Uses one 23A battery (included). includes split ring. Hang packaged.