The Worcester Bosch 1m Flue Extension 7716191083 is designed for use with Worcester boilers in the Greenstar range. This flue extension has a diameter of 60/100mm and is suitable for extending the flue system of the boiler. The product is brand new and is designed for use with storage tank water heaters that are part of a heating system with a boiler. It is a reliable and quality component that ensures proper ventilation of the heating system, ultimately contributing to its efficient performance. Flues are new and still in the box’s. Box’s are perfect but the flues are.