Nichia 405nm Laser Diode is a violet color laser diode LD with 405nm wavelength. Most of the Nichia 405nm Laser Diodes have a module number start by NDV. That means Nichia Diode Violet , such as NDV4642 , NDV means it’s Nichia Diode with Violet Color, the 4642 is the module number. Some Nichia 405nm Laser Diodes have the similar module numbers, such as NDV4642 and NDV4542 .