Killark B7EM - High strength, lighter weight, corrosion resistant copper free cast aluminum construction. Quick release, captivated cover bolts of 316 grade stainless steel for maximum protection from corrosion. Triplelead bolts require only 3-1/2 turns to disengage. Cover o-ring, Nitrile (BUNA-N) material, supplied standard supplied standard for a Type 4X rating. Mounting lugs are bolt on, made from ductile aluminum alloy. Back pan mounting holes predrilled. Conduit and device openings factory or field installed. Aluminum hinges and stainless steel hardware standard on mid to large size boxes. Recessed flange notches to allow for easier cover opening. The B7E series bolted enclosures are for use in locations that are hazardous, corrosive, wet, hose down, dust, dirty, under both sever hot and cold ambient conditions. The B7E series is UL / CSA certified for Class I Groups BCD, Class I Zone 1 & 2 IIB+H2, Class II Groups EFG, Class III, Type 4 & 4X. The B7E are made of cast copper-free aluminum (less than 4/10 of 1%). Supplied standard with a Nitrile (BUNA-N) O-Ring, 316 tri-lead captive cover bolts, and ductile mounting lugs. The boxes have pre-drilled internal mounting bosses for factory or field installed mounting pans. Options include control operators, circuit breaker handles, NPT conduit openings & metric gland openings.