I use Dragon Lasers diffraction gratings, fan and matrix. They are glass and cost 11.99 US dollars and are much better than the flexi ones (I have some Optotronics ones and they are not very good and difficult to use). The DL ones are approx 2.5" x 1.5" I think. If you see in some of my pics, you can see them mounted on an alligator clip. For the fan ones, if you put them landscape, you get a horizontal fan, and if you put it portrait, you get a vertical fan. I have 4 of them and like to mix horizontal and vertical to get nice effects
Hey Danefex, my 450 nm 1w I purchased from you last December is certainly the stud of my collection. It is a GREAT build you did for me! I am happy you enjoy my pics, when are you going to do more burning crystal photo's?