With the aid of a stone cage, the heat of the flue can be utilized better. The steam lasts longer when the sauna water flows from the stone cage to the stones of the sauna heater. This is also a way of decreasing protective distances into flammable material. Stone cages can also be installed on top of each other, which gives your sauna a stylish look. Helps utilize the heat of the flue better Decreases the protective distances Dimensions: 9.8"W (24.8cm) x 9.8"D (24.8cm) x 15.8"H (40.1cm) Designed, engineered, and made in Finland