Fiberglass, triaxial 22 oz/sq yd (744 g/m^2), 25-inch wide. 2 meters worth will provide enough fiberglass for one pair of skis. Generally, the ski core material (e.g., wood) is sandwiched between two fiberglass layers (top and bottom of the core).
SkiBuilder Info: Click here to see tips on using fiberglass (*.PDF file).