I bought a laser, goggles and a shielding from J Tech Photonics and needed a mount for my prusa carriage ! After that getting the laser to run was fairly easy. You will need one M3 nut & bolt (~ 28mm) to attach the mount to the carriage. You can buy yourself a laser and the NECESSARRY safety goggles & shielding from: http://jtechphotonics.com/?product_cat=laser-and-driver-combo-kits Definition of "common x prusa carriage": the carriage that i have :-D Here is the link: http://www.thingiverse.com/thing:18657