Killark MC4 - 360° armor grounding spring is reusable. Copper free aluminum construction for harsh, corrosive and certain hazardous locations. Provides sealing back nut plus inner o-ring seal to prevent moisture ingress to the cable armor and enclosure. Robust threads and world class seal enables easy installation with minimal torque required 360° armor grounding spring is reuseable. Robust threads and world class seal enables easy installation with minimal torque required. Design meets and exceeds third party requirements for cable retention. Provides sealing back nut plus inner O-ring seal to prevent moisture ingress to the cable armor and enclosure. Copper-free aluminum construction for hostile, corrosive, and certain hazardous locations. - Designed for use with jacketed interlocked, continuously corrugated and welded armor cable. Install where it is essential to provide positive grounding to the cable and for a Type 3, 4 connection.