The electric torch (pocket lamp or flashlight) consists of a battery and light in a metal or plastic shell. There is a switch to turn the light on or off. The batteries last for about six hours. An electric torch produces a cone of light about 18 meters long and a radius of 6 meters at the end of the beam. More expensive models have adjustable beams, from a tight beam up to 36 meters long by 1 meter radius to illumination of a 10 meter radius. Other models have a switch which allows a variable brightness, with the dimmer settings allowing for a longer duration.