Killark HKBX - 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, 4-1/4 ID. round body enclosure with a 2-3/4" depth. Option of 2 threaded lens covers and 2 blank threaded cover in 2 depths. The HBX 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 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 (3) ¾”NPT conduit openings, additional openings are available. HKBX series is made of die 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.