The Bigblue 1100AFO 1100 Lumen LED Light with the "Auto Flash Off" added feature. This is a perfect light for the recreational photographer! Bigblue Auto-Flash-Off (AFO) is a photo-cell sensor located on the front of the light that recognizes when your camera strobe flashes and the sensor turns off your light for one second (+/-0.3 sec). While the light is off, only your strobe will illuminate your subject allowing better control of your lighting, and eliminating annoying hot-spots or over-exposure when your focus light mixes with your strobe flash. This light is a rugged, reliable, and compact light with a powerful output. The light source is a XML LED, provides a 55 beam angle with a 6500K color temperature. The light has four output levels/burn times of 110 lumens/ 20-hours in level I, 275 lumens/10-hours in level II, 550 lumens/5-hours in level III and 1100 lumens/2-hours in level IV. The light is powered by a rechargeable lithium-ion 18650 battery. The light switch is a push button activation with battery power indicator. The light body is manufactured from aluminum alloy with an anti-corrosive black anodized finish. The light lens is tempered optical glass. The light has a double O-ring seal providing a 330' (100 meters) depth rating. Bigblue 1100AFO 1100 Lumen LED Light measures (Dia. X L) 1.87" x 5" (47.4 mm x 128.3 mm), weighs 8.68 oz. (264 g) w/battery, on land, and is negatively buoyant 4.76 oz. (-135 g). The Included with the light are a battery charger with indicator light, red filter, lanyard, and owner's manual.