The product is doodlebug design inc part number 1898 "beetle black crushed velvet cardstock". I bought mine at http://store.scrapbook.com/db-1898.html.
This stuff is blacker than Protostar flocked light trap material.
Here's an overall comparison with perpendicular and glancing light, a small square of Protostar laid on a larger piece of the doodlebug cardstock.
Here's a closeup view of the structure, 5X on sensor, 4.4 mm field width. doodlebug on the left, Protostar on the right.
You can see that both materials consist of black plastic fibers adhered on end to a substrate, sticking up more or less perpendicular to the surface. The difference is that the doodlebug cardstock has shorter fibers that stand more uniformly upright, while the Protostar has longer fibers that occasionally lay nearly flat on the surface and provide more area for reflection.
I tested both samples by scraping them with a hard edge to see how much fiber would come off. The difference was minor, slight advantage to the doodlebug.
The other major difference is backing. The Protostar comes precoated with an aggressive adhesive; the doodlebug cardstock is paper you get to glue yourself. And of course the cardstock only comes in 12" squares while the Protostar can be had in big rolls if you like. For most of my purposes, I'm thinking the cardstock is more suitable.
The Protostar sample was freshly cut from my large stock piece, purchased in May 2010. The cardstock was new this month, August 2012.
--Rik
Edit: April 3, 2023, to fix broken link to Protostar.
) However, I don't see this material in Jo Ann's online catalog.