This is a reactive force field that dampens high-energy bursts in the vicinity. It will protect from energy weapons, but not from simple projectiles and basic melee weapons. It does protect from explosions.
This is a low-power version. It is almost invisible when in use, but can be noticed as a slight defraction of light around the user. Turning it on or off is a 1-shot action. EnergyHalo is a more powerful variant.