The R. STAHL Series 8579/31 sockets for Zone 1/21 in 4 and 5-pole versions have full AC3 switching capacity up to 63 Amp. The high degree of protection (IP66) ensures maximum protection against the ingress of dust and water in any application situation. Self-cleaning lamellar contacts provide optimum contact and the plugs can be inserted and removed in the zero position quickly and easily. The load disconnect switch, with a mechanical locking device and a handle that can be locked in the 0 or I position, is an additional safety feature.