PC plugs , sockets and couplings are constructed for extreme operating conditions. they are of easy installation,long life & high reliability. The material is extremely good insulating,unbreakable,wear resistant,longtime durable up to +120℃,resistant against oil,gasoline and salt water,almost non-aging,extremely cold-proof and splash-proof. all units fit not only with the same system but also are fully compatible with units of the same system of other manufacturers,through groove and tongue,joint for same polarity,then it is installed easily through movable cable clamp,use securely and reliably.