MIL-M-43248C, MILITARY SPECIFICATION: MATS, REINFORCING, GLASS FIBER (21 JUN 1982)., This specification covers a group of mats made of randomly oriented strands of glass filaments, with or without surfacing mats and backings. These mats are produced by continuous processes and are used primarily for making glass reinforced plastic items by either the wet layup or matched die molding process (see 6.1). This specification does not cover surfacing mats per se, mats for use in the paneling market, or those made by batch processes or with very short strands.