HIVE Heat 12 LS features a through-the-wall firebox extension that that allows firewood to be inserted from outside the sauna, eliminating the need to bring wood into the sauna room. This highly efficient wood-burning sauna stove is designed for smaller saunas from 212 to 459 cubic feet. Its unique structure allows fresh air to be directed into the burning process from above to create a stronger flame. This allows exceptionally clean burning so that no wood gas escapes the chimney as it does with less efficient stoves. The furnace door is made of cast iron for extreme durability and easy maintenance. HIVE Heat complies with BimSchV II, the strict German standard for wood-burning stoves, to ensure safety and quality. The HIVE Heat sauna stove is treated only with natural oils, without the use of chemicals.