BEST QUALITY AND VALUE! PERIDOTITE SAUNA HEATER STONES These work great for most models of sauna heaters. Our high-quality stones are imported from Finland. This is a special size mixture that we specify, to ensure they fit most sauna heater models. This makes them perfect for replacing your existing stones, or you are purchasing them to go in a new sauna heater. We receive them in factory boxes, however we re-box them to offer the best shipping value through Postal Service, which saves you money. Most orders ship the same day so you'll generally receive within 2-3 days! IMPORTANT! Peridotite stones are a dense, course-grained igneous rock. certain types of stones should be used in a sauna heater. The wrong stones can crack or even explode. These are from Finland, where the best are found. Our stones produce soft heat when water is applied-- which is an essential part of the sauna experience.