Harvia WL400 - Protective Sheath for Harvia M3/M3SLThe Harvia WL400 protective sheath is designed and approved for wood heated Harvia wood burning heaters (Harvia M3 and M3 SL). The protective sheath considerably reduces the safety distance to combustible materials which allows for more peace of mind in smaller environments. The WL400 attaches to the wood burning heater and conforms to the shape. With its slim look and steel black material, the WL400 is sleek and functional.