WW1 On War Service 1915 munition workers badge J.R.Gaunt 'M'

A good original First World War official 'On War Service 1915 munitions workers badge'; Crowned oval title, the voided centre bearing the 'Board of Ordnance shield', the reverse impressed with maker's details stamped in relief 'J.R.Gaunt & Sons Ltd London' 'M' and impressed with official issue number '79210'. Very good condition, complete with original buttonhole fitting.Height 44mm.