The AC3020 Harvia sauna stones are selected according to ancient Finnish tradition. The broken stones, measuring 10 to 15 cm, are designed for both wood stoves and less powerful wall-mounted electric stoves. They can store enormous amounts of heat, allowing the poured water to effectively evaporate over the large surface area of the broken edges. Furthermore, the broken stones are easy to stack and allow for good air circulation, making them perfect for a luxurious sauna experience. A sauna session with high-quality Harvia products is always a wonderful experience. Technical specifications: Manufacturer: Harvia Diameter: 10 - 15 cm Weight: 20 kg Melting point: 1400 °C Compressive strength: 13.2 MPa Material density: 3.02 g/cm³ Water absorption: 0.1%. Please note for commercial use.