This is an amazing flashlight! This flashlight uses a LED bulb. The lens is glass and is ultra clear. It has five light modes: high, medium, low, strobe, and SOS. You can widen the area that is lit and focused by pulling the head of the flashlight outwards. When you pull the head of the flashlight all the way out there is a small lit square, then when you push back the head of the flashlight it widens the lit area. When you zoom in the lumen is 300 and when you zoom out the lumen is 1000. The light is nice and bright. When the flashlight is fully extended it is a little over 6″ long. When the flashlight is not extended it is a little under 5.5″ long. This flashlight is VERY durable and strong. It is also VERY well made. An excellent added plus is on the end where the bulb is, there is a silver ring that is lotus style escape window breaker. There is a protective plastic sleeve around the bulb that helps avoid damage to the LED bulb. This flashlight is waterproof and shock proof. This flashlight is impact resistant and made from lightweight high-grade aluminum alloy materials that resist rust and corrosion. It is easy to turn the flashlight on and off. To turn the flashlight on and off there is a orange anti-slip waterproof rubber button located at the end of the flashlight. The flashlight also has a wrist strap.