This DuraFlex SS 6 InchDuraFlex Spacer is the ultimate in flexible components for strength and flexibility. The DuraFlex spacer is used to maintain a 1 clearance with flex sections of DuraLiner and DuraFlex SS. Not for use with Ventinox flex. Features. 6 in. DuraFlex Spacer. Single wall constructionSpecifications. Inner Diameter 6. Pipe Inside Diameter 6. Vent Pipe Size 6. Configuration Spacer. Pipe Class Flexible Liner. Pipe Shape Round. Fuel Type Coal, Gas, Oil, Pellet, Wood, Wood/Oil/Coal. Collection DuraFlex SS