PelletVent Pro Applications: For stoves and inserts that use wood pellets and oil fuel. Also designed to vent biofuel products such as grass, corn, switch, cherry pits, soybeans, coffee buffalo, sunflower husks, hickory and wheat shells. Use to add length to PelletVent Pro tubing. 12" Tubing Add 3"-10" of length. Listed to UL 441. Marketed exclusively to the Specialty Hearth market. Welded (not stain or pop welded) 304 Stainless Steel. Snug fit construction allows for ease of twist-lock connections while eliminating leaks - no gaskets or sealants used. Important: Pellet Vent Pro tubing is not interchangeable with standard Simpson Dura-Vent pellet or corn vent. Note: 1 1/2" deduct for installed length. Construction and Materials: Laser-welded Dual wall tube with a super-ferritic stainless steel inner wall and a .018" laser-welded Galvalume outer wall. Painted black exterior available. Primary metal-to-metal connection joint. Encapsulated O-ring provides a secondary seal. Clearances: 1" Clearance to appliance fuels using corn and other biofuels, wood pellets or oil.