PURPOSE For improving the safety and health protection of workers potentially at risk from explosive atmospheres (Zones 1 and 2,Gas groups IIA, IIB, IIC), such as offshore oil and gas platform, marine vessels, refining and petrochemical industries, food processing, pharmaceutical , breweries and distilleries as well as firefighting, water treatment and gas distribution. STANDARD: Resolution MSC.98(73)、 EN60079-0: 2012+A11: 2013 / IEC60079-0: 2011, EN60079-11: 2012 / IEC60079-11:2011, EN 60079-28: 2015 / IEC60079-28:2015 MAIN TECHNICAL SPECIFICATIONS: Dimensions: Ø 50mm x 181.5mm Weight: 150g (without battery)