Neoprene bushing compressed by cable collar prevents entrance of water, bushing is highly resistant to hydrocarbon deterioration and is self extinguishing|Locking screw and slot prevents plug cable collar from backing off|Contacts exert constant pressure along entire contact surface and provide electrical continuity|Insulating blocks provide greatest dielectric and mechanical strength and lowest arc tracking|Positive polarization only plugs and receptacles of same style, number of poles and current rating can be used together|Controlled length contacts ensure that ground makes first and breaks last for added safety|Made of copper free aluminum