From the post:
20mm Laser Cut Acrylic Sci-Fi Bases for 15mm Miniatures (12)
These are laser-cut Acrylic bases with a sci-fi hexagon pattern etched on them. They come in clear, but are easily painted with standard paint.
They are almost exactly the same size as a US Penny.
Check out the Videos tab for tutorials on how to cut off the integral base on many 15mm miniatures and attach it to the Acrylic base.
They come 12 to a pack.
Note: They come with a blue protective film that should be removed before priming or painting. It will simply peel off.