Its a wax impregnated fibrous cardboard. Instructions on use are demonstrated here.

http://www.youtube.com/watch?v=stlk1IrplAk

Its also a quite inexpensive tinder and can be stored in a PSK in a more compact fashion compared to waxed cotton balls.

http://www.surplusandoutdoors.com/shop/s...our-362407.html

another favorite tinder is bicycle repair rubber tyre solution such as a tube of Halfords Bike Tyre rubber solution.

http://www.halfords.com/webapp/wcs/store...tegoryId_228377