Laser Cutter Mirrors Calibration Jig V2

These 3D printed jigs holds piece of paper/card to 2nd and 3rd mirror mounts during CO2 laser cutter beam calibration. No more guessing where hole is or sticky tape mess. These were designed to fit Shenhui Laser SH-G350 (a.k.a. Blue/White 50W eBay laser) mirror mounts. Yours may vary.
Warning: If your mirrors is badly out of alignment laser might strike and burn this jig. Always ware laser safety glasses!
Update: This is update to the original 2nd mirror calibration jig. Now you can calibration both mirrors. Additionally I added "ears" to hold jig to 3rd mirror with rubber band (it was falling off constantly). Handy "hanger" ring now also included.
I also included template for paper/card "target" inserts.
Sketchup files as well as Adobe Illustrator and DWG included.
Update 05/02/2015: Fixed paper target templates. Now includes project file for RDWorks/LaserWorks (calibrated for 50W cutter).
Update 06/30/2015: Here's small tip. No need to remove second piece when replacing paper target. Just lift it slightly and pull/push paper in/out. Can make those targets slightly longer for easier removal.
Let me know if you have any questions in comments.