HUMM Extra Small 33 lbs 1" - 2" Gray Rounded Olivine Granite Sauna Heater StonesProduct range of HUUM includes round sauna stones with a diameter of 35 cm and 510 cm. Olivine diabase sauna stones are enduring and their thermal capacity is high. Its recommended to use round sauna stones in HUUM sauna heaters. Round stones complement the design of the heaters and provide milder steam. 33 lbs of 1" 2" (3 5 cm) of rounded olivine sauna stones. We highly recommend using rounded stones in HUUM heaters to compliment the design and have