Double wall stove pipe is used to make the connection from the chimney or chimney kit to the appliance in the final interior run. 

Double wall stove pipe can reduce the clearance needed to combustibles in many situations and typically has a stainless steel inner wall that will provide a much loger time of service that a typical single wall setup.

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    Simpson Dura-Vent DVL                               Selkirk DSP Double-Wall