This is a 445nm 2.5W laser diode mount with support for two line lasers for positioning.
There is a battery holder for a C2025 battery and push button switch to power the line lasers. I glued it on the back of the laser mount with super glue after wiring it.
The 2.5W laser is from eBay. http://www.ebay.com/itm/231968432876?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The line lasers also from ebay. http://www.ebay.com/itm/222120750683
A word of caution if you buy the 2.5W Laser Diode mentioned above. Mine had the TTL input wires reversed. The seller was notified and has since corrected the photo showing the diodes polarity. The white wire is + and the blue wire is - and what they don't tell you is that if the TTL input is left open and not connected to anything, when you plug in the 12 Volt supply, the laser will activate! Be very careful with these lasers as they are dangerous and you should always were protective goggles when around them.
I modified the Marlin software to output the FAN to a 5 volt TTL PWM logic level on the RAMPS 1.4 board since I drive the RAMPS at 12 volts and the D9 output would damage the diode driver. I will provide more information on this later.
EDIT: Added original MPCNC version. Note: I have no way to test this as I only have the updated MPCNC machine, but I took the part that mounts to the CNC machine from another stl file and hacked it to fit my laser mount.