The sand timers are made of pure wood and heat-resistant tempered glass. Sand timers are for inside sauna use and allow you to monitor a fixed time interval of 5, 10 and 15 minutes. It is best to fit the timer to the opposite wall from the heater and control it by simply rotating it. Even with prolonged use, the accuracy of the watch remains the same thanks to the uniform graininess of the annealed and sifted sand.
