The PMF 120 unit is the foundation of our PEMF devices. It has an intensity dial that you adjust from 1 low to 10 high in strength. These Spark Gap Units are designed for Office / Home use or for those that need the flexibility to move them around-On the go. This unit has a Spark Gap Chamber to create the units power. It is ready for 110v USA or 220v International power requirements. The weight of the unit varies on the type of unit you select. This unit has been safely used in the US and Internationally for many years.