Harvia 1.64ft Single-wall Stove Pipe 4.5" diameter-Black | WZ050MHarvia 1. 64ft Single wall Stove Pipe 4. 5" diameter Black WZ050M This can be used for your custom chimney setup or to extend the length of the Harvia wood fired sauna stove chimney kits. It complies with all international fire and operational safety requirements to help keep your heater safe. Features Single wall stove pipe (non insulated) For use inside in open air area (use double wall when passing thru wall ceiling) Fits on all Harvia wood fired