The first red laser pointers were released in the early 1980s. Red laser technology has come a long way from those low powered red keychain lasers. Red laser pointers, being the most common, have visual lengths at 670 nanomenters (nm), 650nm and 635nm. Laser pointers with 670nm wavelengths are often the cheapest and weakest, while those that are 650nm are stronger, but 635nm laser pointers are the easiest to see and usually more expensive. These laser pointers can be the size of a pen and are used by teachers, instructors and presenters to highlight words, charts, diagrams and other information.
