The 501040-0005 PTFE-Teflon® Insulator Heater Jacket Kit is designed for 4.0 inch diameter vacuum tubing straight sections that are 1.0 inch long. The kit comes with 5 individual 1 inch long insulators. Series 49UL insulators keep heat from escaping for better temperature uniformity in vacuum piping applications. PTFE-Teflon® 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.