HUUM Sauna Stones, 5-10 cmOriginal HUUM sauna stones (15 kg) We highly recommend using rounded stones in HUUM heaters to complement the design and have milder steam. In our selection, we have rounded olivine diabase stones in three different size ranges: 3 5 cm, 5 10 cm, and 10 15 cm. The stones are durable and have high heat capacity. You can also use other types of stones in HUUM heaters, except decorative stones because they can break easily. Choose your stones wisely