8" DuraLiner 8-1/2" - 12" Adjustable Sleeve 8DLR-AS 8" DuraLiner Adjustable Sleeve is used for inserts with rear exhaust outlets. Sleeve adjusts from8 1⁄2” to 12”. Diameter: 8" Length (adjustable): 8 1/2" to 12" Sturdy construction for long-lasting durability