The Burnham Boiler 105651-01 Rear Insulation Disk Kit is a genuine replacement insulation component designed for compatible Burnham Alpine and K2 series boilers. Installed at the rear target wall of the boiler, it provides thermal insulation by limiting heat transfer and reducing unwanted heat loss during operation. This insulation disk helps maintain consistent operating temperatures... https://www.partshnc.com/105651-01-burnham-boiler-rear-insulation-disk-kit