Harvia Stainless Steel Chimney Extension. 5M (19 5/8) for Sauna Heater WHP500. The WHP500 chimney extension is a stainless steel.5 m insulated chimney pipe that pairs with the WHP1500 Chimney Kit. This item is in the category "Home & Garden\Yard, Garden & Outdoor Living\Pools & Spas\Sauna Heaters". The seller is "saunaplace" and is located in this country: US. This item can be shipped to United States.