A series of field tests were performed to assess the initiation and detonation of certain types of explosives under jet attack. These explosives are candidate to be used in the Explosive Reactive Armors boxes (ERA). The used explosives were four different formulations of pressed Plastic Bonded Explosives (PBX S) prepared on site and a selected type of sheet explosive. The used conical shaped charges and detonators were prepared on site. The Plastic Bonded Explosives were prepared using Hexogen explosive and the energetic binder Fluorel. The produced PBX S beads were pressed in a special mold to a density of approximately 1.6 g/cm 3 in order to fabricate explosive sheets with certain dimensions. The residual depths of penetration of the jet in the mild steel in the presence of these compositions have been measured experimentally.