Diameter 5 1/2 . Length 35'. Construction Material 316Ti single-wall .005 stainless steel flexible liner. Clearances 0 clearance to masonry for gas, 1 clearance for pellet and oil stoves, for wood-burning applications, insulation is required for 0 clearance to masonry. Listed to UL 1777 MH14420 and ULC S635. DuraFlex 316TiSS Chimney Liner is for use with pellet, non-condensing gas, wood burning, and oil appliances. Available in diameters of 3 8 and lengths of 15', 20', 25', 30', and 35', the liner is made from single-wall 316Ti titanium stainless steel. 316Ti SS is designed for harsher conditions, for more resistance to corrosion, such as coal. DuraFlex SS flexible relining is designed for masonry chimney's and for use with gas, wood pellet, oil, or wood appliances. Including fireplace inserts, furnaces, boilers, and water heaters. DuraFlex SS relining systems ensure safe and efficient venting of heating appliances while protecting the masonry chimney from the damaging effects of flue product condensation. DuraFlex is available in 304 and 316Ti stainless steel. The 304 and 316Ti SS are designed for use with pellet, non-condensing gas, and oil appliances. DuraFlex SS and 316Ti SS, when used with the Simpson DuraVent Two-Ply Insulation Sleeve, may be used for relining wood burning fireplace inserts and stoves to meet UL 1777 and ULC S635 standards with 0 clearance to masonry.