The product is used to connect 6″ / 150mm diameter matt black enamel stove pipe to 5″ / 125mm diameter matt black  vitreous enamel stove pipe.

Additionally, it can also be used where the stove collar (circular housing piece attached to either top or back of a stove) measures 5″ / 125mm but the installer wishes to use 6″ / 150mm matt black vitreous enamel stove pipe before connecting to flexible liner, twin wall rigid flue or clay pot adapter.