The HUUM 24 Replacement Stones – Small are rounded olivine diabase sauna stones made for refreshing HUUM heaters where the original stones have fractured. They are supplied in a 33-pound box.
Dense olivine diabase tolerates repeated high-temperature cycles, storing heat and releasing it gradually, so water ladled over the stones produces softer, more stable löyly rather than short, harsh bursts of steam. The rounded stones pack tightly with minimal gaps, promoting even airflow through the heater basket and more uniform heat distribution. They are selected to resist cracking and glazing under repeated heating and cooling, and their sculpted shapes complement the open-basket design of HUUM heaters.