Killark HK2D - 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. HK Series covers are cast from a copper-free aluminum alloy. All covers have shrouded tamper resistant set screws as standard which can help to combat excessive vibration in rugged settings. Lugs on cover permit easy removal and tightening.