When sourcing Ultem (Polyetherimide), the price is heavily influenced by the grade and resin type. You must distinguish between Ultem 1000 (unfilled), Ultem 2300 (30% glass-filled), and Ultem 2100 (10% glass-filled). Key performance metrics include a Glass Transition Temperature (Tg) of 217°C, high dielectric strength, and inherent flame resistance (UL94 V-0 or 5VA). Ensure the supplier provides a Certificate of Analysis (COA) to verify that the mechanical properties, such as tensile strength (approx. 105 MPa for unfilled), meet your specific engineering requirements.