Typical markings for a CO2 fire extinguisher cylinder according to PED M25 x 2 = Thread Specification - Important to ensure the correct valve is used with your cylinder.UK = Country of ManufactureLUXFER = Cylinder ManufacturerL3158V....= Cylinder Type Number and Serial Number - This number is recorded by Luxfer which means, if ever necessary, the entire manufacturing history of your cylinder can be traced. AA6061 T6 = Alloy of Construction4,4MM = Design Minimum Wall Thickness.2,4KG = Empty Weight of Cylinder Only (kg)3L = Minimum Water Capacity (litres)PT 212 BAR = (Test Pressure) - Shows the pressure that the cylinder should be tested to - this must not be exceeded.2 KG CO2 = Charge WeightPS 169,3 BAR AT 60°C = (Service Pressure) - Shows the maximum service pressure and operating temperature for which the cylinder design is approved. TARE 2,9 KG = Weight of Cylinder plus valve and, if fitted, dip tube.GROSS 5,9 KG = Tare Weight plus Charge Weight. (Optional)This is the mark of Conformity and Notified Body Reference Number according to the Pressure Equipment Directive 97/23/EC. 2002/10 = (Test Date) - Year and Month of initial test.