Ultem PEI is an amorphous, amber-to-transparent thermoplastic with characteristics similar to the related plastic PEEK. Relative to PEEK, PEI is cheaper, but is lower in impact strength and usable temperature.
Ultem resins are used in medical and chemical instrumentation due to their heat resistance, solvent resistance and flame resistance. Ultem 1000 has a high dielectric strength, natural flame resistance, and extremely low smoke generation.
Ultem has high mechanical properties and performs in continuous use to 340 °F (170 °C).