The Harvia Linear 18 Compact Sauna Stove possesses an incredibly sleek double shell structure for flexible installation options. Constructed from a robust black steel double-shell, the Linear 18 significantly decreases the structures heat radiation for shorter safety distances and flexible installation in different areas of your sauna. Adjust the air circulation of the heater using the ash box to control swift heat-up times and regulate temperatures for efficient, long-lasting sauna sessions. The crystal-clear glass hatch beautifully illuminates your cabin's interior with flickering flames for a relaxing and rejuvenating wellness experience. Required sauna stones 88 lbs (2 boxes) sold separately.