Forever® Vent 4" x 30 ft Double Ply SmoothWall™ Flexible Chimney Liner Coil

Double Ply SmoothWall™ Stainless Steel .012 thick material. Corrugated outer ply provides maximum strength and flexibility, and its SmoothWall™ inner ply improves the chimney's draft up to 20%. It cost more, but it is well worth the extra expense. Tested and approved to UL1777 zero clearance standards. You won't find a better double-ply chimney liner anywhere, guaranteed! "The Chimney Liner That's Preferred By Professionals"™. Stainless Steel Lifetime Warranty. Made in the USA.