The safety valve (Volta rigidity) automatically prevents the pressure of the previously set gas pressure. In other words, if required, the required amount of gas, water vapor or air is drained so that the pressure of the device reaches the size permitted.
Types of Firmness:
1- Hardness even with spring
2. Firmness, weight, weight
3. Firmness, even with springs and diagrams
In selecting tightness, the following should be considered:
1. Working pressure
5. Bandage adjustment