I buy these little laser modules on Ebay, they are cheap, around 10 for a dollar if you shop around and are willing to wait for a month. Or you can get 10 for 5 bucks and only wait a few days. They run on 5vdc. They measure 5.9mm diameter and there is a flat little protuberance at that back that the wires are soldered to, it measures 6.2mm wide. Overall length including the protuberance is 13mm. I adapted a gopro mount to work with these little laser modules. My plan is to print 6 to 10 of these and use them as part of my Christmas lights display this year. 3 or 4 opposite each other flashing back and forth. Like a mini laser show at a concert. I placed the gopro mount and the laser head holder on a common 0.5mm brim for easy printing. You will need an 8-32X3/4 screw and an 8-32 nut. Printed in PLA .2 layer, 100% infill

DISCOVERY: These little lasers aren't bright enough to do what I wanted. Unless I make a fog machine too. The mounts fit nice, but don't get your hopes up for a laser light show.