These are great for rapidly working out which cylinder or cylinders are miss firing on a multi cylinder engine, simply by measuring the temperature of the exhaust headers. In the old days we would spit on a finger and gently touch the exhaust header determining the hottest by the sound of boiling spit or the smell and accompanying pain of burning flesh, if one wasn't quick enough. Having used both methods, all at Biker's Toolbox agree that for slightly over thirty quid it's a no brainer.- Range -50? to +650?C (-58? to +1202?F), selectable from fahrenheit to centigrade. Includes backlight, hold and MIN/MAX data recording.- CE, UKCA & RoHS compliant.- Distance to spot 12:1. - 1 x 9V battery <<- Auto power off with automatic data hold and laser target pointer.