Explosión proof ,, Appleton control Assembly body for hazardous locations ,, this is a metal box use in industrial areas or gas stations or areas where is gas or Fumes that can cause an explosion in case of an electrical short or spark this box is designed to prevent and contain any sparks and prevent explosions this item is hi dollar this is electricians special , I have 20 of this , if any body is interested on all them we can negóciate better price