Tim Smith & CGBlack,
I purchased mine through a local building specialties (wholesale) supplier. They carry only ceiling grid systems, dry wall finish products and insulation. The SelectSound product is manufactured by Owens Corning (This supplier carried both OC and JM products but it was easier for them to get the OC for some reason).
It's black all the way through, with black felt applied on one side (obviously made for theaters). It is every bit an equal to TheaterShield: if you look at the performance specs of both products they are so close that the difference IMHO is probably in testing criteria & methods than in actual product differences.
I prefered the sheet type over the roll type as I found it much easier to work with and install. It was installed using small dabs of standard construction adhesive (dabs about 8" on-center) on the backside of the product and pressed into the 1" recesses built into the walls (i.e. no nail or screw heads under the fabric). BTW, it cuts like warm butter with a standard blade knife. I used Mellotone brand UL listed (fire retardant) architectural grade acoustical fabrics as the finish covering (in lieu of Gilfords of Maine cloths).
I paid about $32 a sheet for the SS and it comes in bundles with ten sheets each (each sheet was 48" x 96" x 1"). Took about two weeks to ship in.
FWIW, this material performs great in my HT plus it was easy to work with. Testing with my TerraSonde ATBPro acoustical analyzer (1/12 ocatave RTA and 1/3 octave RT-60) bore this out.
Thumper