Adjustable length 4" x 12" Pellet Vent Pipe. PelletVent is a complete venting system from DuraVent for stoves and inserts that use oil fuel or multi-fuels, including wood pellets, corn, cherry pits, switch grass, coffee husks, walnut shells, soybeans, wheat, sunflower hulls, rapeseed and sugar beets. The adjustable double-wall chimney stove pipe adds 3 - 10 inch to a rigid vent pipe and fits most standard piping. Its double-wall, air-insulated design offers superior performance and reliability for long-term use. For added durability, PelletVent seams are factory-sealed on all elbows, tees and fittings.