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.
