TRIC Case Deluxe FolkTRIC Case for Folk Guitars High Tech Impact Resistance Made of Expanded Polypropylene, which is the same shock absorbent, high tech material used by the automotive industry in bumper cores, it can also be found in the manufacturing of bicycle helmets. The high impact resistant material trusted to save the human head is now available for your acoustic guitar. Heat, cold and moisture beware!! TRIC stands for 'Thermally Regulated Instrument Case.'