The LPM635-03C Laser Diode Module is an economical choice. It includes the diode and collimating optics in a single case. This Fabry-Perot (FP) 635 nm Laser Diode Module with 3 mW CW circular beam (using a microlens) comes in a self contained module. It requires a 5 VDC external power supply. An LPMS-5-110 or LPMS-5-220 Series Power Supply (not included) must be used with this LD module to meet CDRH requirements by providing an interlock input, key enable switch, delayed start-up, and laser active indicator. Warranty is not applicable when a custom power supply is used to drive the module.