BS4343; IEC309; Eex de IIC T6; ATEX; PTB ATEC 1039. CEAG Enhanced Coupler. CEAG Crouse-Hinds enhanced BS4343 (IEC309) plugs, sockets and couplers are designed specifically for hazardous area environments. The Enhanced ranges offer mechanical advantages over the popular and widely used Standard versions. The Enhanced version will ultimately replace the Standard range. Patented plug and turn connections Ingress protection to IP66/67 Suitable for Zone 1 and Zone 2 applications, and also Zone 21 and Zone 22 dust applications. CEAG Standard hazardous area plugs will mate with Enhanced sockets and couplers CEAG Enhanced hazardous area plugs will NOT mate with standard sockets and couplers. Couplers will accept Enhanced and Standard Plugs