Circular Paper Discs prevent hot-mix asphalt samples from sticking to baseplates or compaction heads in Marshall or Superpave Gyratory Compaction Molds. The discs are 0.007-0.008in thick and made of 100lb paper stock, and meet ASTM and AASHTO standards. MSA-121 discs are used with 6in and 150mm molds, and sold 500/package.