Whether you prefer a Finnish sauna, a bio sauna, an infrared cabin, or a banya: Regardless of the type of sauna you choose, a single sauna session is generally recommended to last no more than 15 minutes. During this time, the sauna experience exerts its positive effects on the cardiovascular system without overtaxing the body. This hourglass, crafted from solid beech wood, helps you keep track of the recommended time. Beech wood is ideal for the sauna because it is very dense and sturdy and particularly heat-resistant. The narrow neck of the glass tube and the size of the sand grains are perfectly matched so that the black sand—which is clearly visible even from a distance—trills down precisely within the time indicated on the scale. With your eyes on the hourglass, you can calmly enjoy the soothing 8 to 15 minutes of your sauna session before cooling off again for about 20 to 30 minutes.