Killark HK4D - Threaded blank screw covers provide easy access to interior. High strength, lighter weight, corrosion resistant copper free cast aluminum construction. Cover o-ring, Nitrile (BUNA-N) material, supplied standard supplied standard for a Type 4X rating. Electrostatically applied gray powder epoxy/polyester finish on exterior of covers. Covers have shrouded tamper resistant set screws as standard. Small compact, 3-1/2 Dia. round body enclosures, two single port depths to choose from. Also available in a double port style. Option of 4 threaded lens covers and 4 blank threaded cover in 4 depths. The HK series is for use in locations that are hazardous, corrosive, wet, hose down, dust, dirty, under both sever hot and cold ambient conditions. They are UL / CSA / FM certified for Class I Groups BCD, Class I Zone 1 & 2 IIB+H2, Class II Groups EFG, Class III, Type 4 & 4X. Also, ATEX, IEC Ex, Ex db IIC, Ex e IIC, Ex tb IIIC T4…T3 IP66 with suffix “C”. Supplied with ¾”NPT conduit openings, additional openings are available. HK series is made of cast copper-free aluminum (less than 4/10 of 1%), supplied standard with a Nitrile (BUNA-N) O-Ring, internal external ground (earth) screws, stainless steel tamper proof locking set screw and electrostatically applied grey powder paint. Internal “X” pad for mounting instruments or terminals.