Air Mixing Technology- Saunum's patented air blending system mixes cold, oxygen-rich air from the floor with hot, oxygen-poor air from the ceiling. This solves the discomfort many associate with saunas. Whether you like it extremely hot or just warm, Saunum delivers full-body heat and oxygen. European Design- Featuring an elegant black steel finish, Saunum combines Scandinavian design with premium materials. Massive Stone Capacity- Stones are the heart of a Nordic sauna. A large 132-pound stone capacity (requires 4 boxes, sold separately) results in softer, more even heat and luxurious steam. Himalayan Salt Reservoir- Himalayan Salt Spheres are placed within the air stream to distribute beneficial salt ions throughout the sauna. Designed for sauna rooms from106 to 212 cu. ft.