The Vaillant EcoTec Plus 824, 831 & 837 set of 3 control knobs 0020074963 is a vital boiler part designed for use in heating systems. This set of control knobs is specifically manufactured by Vaillant, a trusted brand in the industry, ensuring quality and compatibility with their boilers. Perfect for DIY enthusiasts or professionals looking to maintain or repair their Vaillant boiler, these control knobs provide the necessary components to keep your heating system running smoothly.