The DuraFlex SS system is designed for efficient ventilation of heating appliances while effectively protecting your chimney from the damaging effects of condensation in the flue. In order to meet the UL1777 standard for masonry chimneys and fireplaces, when installing the DuraFlex Zero Clearance Insulation Sleeve, utilize this DuraFlex SS 6-ft Mortar Sleeve for 4 inch Chimney Liner. At 1" larger than the nominal diameter, this liner is designed to complement the DuraFlex UltraPro 4-in. chimney liner pipe. It is also available in 5", 5.5", 6", and 8".
- UltraPro 6-in. Mortar Sleeve
- Designed for Dura flex UltraPro 4-in. chimney liner pipe
- Actual diameter is 1" larger than nominal diameter
- Available in 4", 5", 5.5", 6", and 8"