CO2 lasers are also referred to as carbon dioxide lasers, and was one the first gas lasers to developed. CO2 Lasers were invented by Kumar Patel of Bell Labs in 1964, and are still one of the most useful lasers. CO2 Lasers are are the highest-power continuous wave lasers currently available and very efficient, and the ratio of output power to pump power, can be as large as 20%. CO2 Lasers produce a beam of red light and the principal wavelength bands centres around 9.4 and 10.6 micrometers. CO2 lasers are used in industry for cutting and welding and they are also extremely useful for some surgical procedures, an example being skin resurfacing, which is the burning of the skin to promote collagen formation. CO2 Laser are also used for military purposes such as range finding, because the atmosphere quite transparent to infrared light.