The 502020-0807 Polyimide Flange Insulator is designed for use with NW50 size ISO-KF flanges with 2.0 inches vacuum tubing on one side and a hose or bellow tubing on the other side that is clamped with a model 100318806 ISO-KF toggle flange clamp. Series 49UL flange insulators keep heat from escaping at flange connections for better temperature uniformity in vacuum piping applications. Polyimide constructed heater jackets can be used in all critical applications where minimal outgassing, ultra-low particle generation, elevated temperatures up to 200°C, and ease of installation are required. These patented heaters are constructed with fully squared ends and a form fit shape to maximize thermal efficiency and temperature uniformity, minimizing thermal losses and power consumption.