Each volt on a tube means 1 bonus point to an ability. Therefore, a 3-volt would be able to give 3 bonus points, while a 5-volt can give 5 bonus points. An exception is the health boost, which increase the health stat by 10 points per volt. Each Tube resembles a vacuum tube. A vacuum tube is an early electronic device, superseded by transistors and diodes, yet are still found today in high-powered radios.