High Energy Raio Frequency weapons (HERF) or High Power Radio Frequency weapons (HPRF) are weapons that use high intensity radio waves to disrupt electronics. They are a type of directed-energy weapon. They operate similarly to electromagnetic pulse (EMP) devices, by inducing destructive voltage within electronic wiring. They are usually directional and can be focused on a specific target using a parabolic reflector. Faraday cages may be used to provide protection from most HERF and EMP effects.