Shields, less commonly called grav shields, are pressure-gravity waves which are impervious to all forms of energy and which violently disrupt electronics. Therefore, they are effective protection against energy weapons, low-mass projectiles, and missiles. Because of their immense power requirements, shields rapidly flicker on and off. Weapons mounted on the shielded vehicle are fired as the shield flicks off, and all of the vehicle's electronics are in sync with its flicker rate.
Shields do not deflect objects which mass greater than 100 grams (0.1 kilogram). Shields are rated in terms of their flicker rate; the higher the rate, the less likely they are to be penetrated, but the more power they require.