Scandia naturall sauna rocks are crucial for retaining and distributing heat, making them an essential component of any sauna experience. Naturally resistant to extreme temperatures without crumbling Sourced from select rivers and beaches in Mexico, North America Rocks will not discolor, fade, or crumble Each box contains 25 lbs of sauna rocks Small & Medium Heaters, 3KW-9KW - Take one Box Large Heaters- 12KW-18KW - 2 Boxes