SRUC (Solvents): Durable polypropylene construction protects parts from spilled solvents and other chemicals, plus from impact in rough work environments.
ET (Extreme): Even more durable thermoplastic rubber protects it from very rough work environments, plus from jet fuels, grease and other chemicals.
CM (Conductive Material): A network of carbon nanotubes insulates sensitive parts, such as electrical components, from Electrostatic Discharge (ESD).**
UT (Ultraviolet Reactive): If a spring, lid or other Trey® component breaks off and disappears, shine an ultraviolet lamp and it will literally glow in the dark.