One of the hardest things to do with your new eBay Chinese CO2 Laser Cutter & Engraver is to align the mirrors so I whipped up this set of of three 3D alignment jigs for the laser. As the first fits over the secondary mirror while the second fits over the cutting head of the laser unit (i.e. down mirror and lens). You than slip in a paper target (preferably of card stock nature) and set the laser to the lowest setting and do a test fire of laser (follow all safety precautions before firing the laser). Now adjust your mirrors accordingly until the target is dead center. Now be careful! Paper burns and so does plastic! So use the laser only at a low power level and for VERY short bursts of time to avoid flames, also ensure you have have an appropriate fire extinguisher handy at all times when working a laser!