Harvia M3 Protective Sheath (side)Harvia M3 Protective Sheath (side) The Harvia WL400 protective sheath is designed and approved for wood heated Harvia stoves (Harvia M1, M2, M3 and M3 SL). The protective sheath considerably reduces the safety distance to combustible materials in practice, this makes the stove fit in a smaller space. The protective sheath is attached to the stove and conforms to the shape of the stove, making the combination sleek. As the Harvia protective sheaths are