TUFFStik® Nail Base is a tough, fiberglass reinforced, film surfaced base sheet designed as the anchor sheet in self-adhesive roofing systems. Intended to be mechanically attachment to nailable substrates or through approved insulations to nailable substrates. Contains a fiberglass mat reinforcement strategically placed within the compound and is surfaced with a permanent film on the top side to enhance mating with compatible TUFFStik® SA BASE or SA CAP. The underside is finished with a fine mineral release agent. Not intended for use with hot asphalt, cold adhesive or torch applications.