DIY Mini CNC Laser Engraver. - Instructables
The laser I've used is Focusable Laser Module 200-250mW 650nm. The outer metal housing work as a Heatsink for the laser diode. It has focusable lens for the adjustment of laser dot. Connect the laser wire terminal to the laser socket on the driver board. You can get one Here. DIY Mini CNC Laser Engraver.: Page 15