... 2006,IEC 60079-31: 2008Material EnclosureCopper-free aluminium, powder coated external surface,yellow (RAL1021)Glass coverToughened glass, stands ... constant current, surge-proof andanti-electromagnetic interference, and protection against overcurrent, open circuit, and short circuitExposed fastenerStainless steelLamp ... /W, high colourrendering, long service life (50000h), environmental protection.