The Flex King Pro has a smooth inner wall making it a great liner for wood or coal. It increases draft and reduces creosote buildup with the use of wood burning appliances. The Flex King Pro can used for all fuels. It is a great option to use with gas and oil appliances because it can handle 25% more BTU's than the standard Flex King Liner.
The Flex King HD is best to use if you have a wood stove or furnace that you plan on burning all winter. If you rely on the wood stove to heat your home, this is the liner you need! It is the strongest, most durable flexible liner we make. As you can see it is also smooth reducing creosote build up.
All of our Chimney Liners are UL listed to UL1777.