UNILETS® ER explosion proof and dust-ignition proof conduit outlet boxes for use with threaded rigid metal conduit. Meet a wide range of classified area requirements. Corrosion-resistant — ideal indoors or out. Connect conduit lengths and change direction of conduit. Provide access for maintenance. Compact, rectangular conduit outlet boxes are ideal in classified locations where space is limited. Ground surface contact between body and cover assures a flame-tight joint.