Typical markings for a permanent gas cylinder according to TPED 25E = Thread Specification - Important to ensure the correct valve is used with your cylinder.GB = Country of ManufactureLUXFER = Cylinder ManufacturerP3136Z ....= 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 Construction11,8MM = Design Minimum Wall Thickness.12,4KG = Empty Weight of Cylinder Only (kg)10L = Minimum Water Capacity (litres)PW200 BAR = (Working Pressure) - Shows the pressure that the cylinder should be filled to - this must not be exceeded.PH300 BAR = (Test Pressure) - Shows the pressure that the cylinder should be tested to - this must not be exceeded.p 0038 = The mark of Conformity and Notified Body reference number to the Transportable Pressure Equipment Directive 1999/36/EC. e2UK907 GB = Pattern Approval number according to Directive 84/526. Replaced by EN1975 when this specification is design basis. [STAMP] = Stamp of Notified Body.2002/09 = Year and Month of initial test.