Thermoforming is the process of heating plastic sheets to a pliable temperature and forming them over tooling to create a usable shape. Gemstar employs three thermoforming processes: vacuum forming, snap-back billow forming, and pressure forming. Each is appropriate for different characteristics in the finished part. Starting gauge thicknesses range from .093 to .275. Stock materials include high-density polyethylene, ABS, and polycarbonate. Custom colors and conductive, flame-retardant, and medical grade options are also available.