Custom Fit OEM Gauge for Current MDE Jubilee Gun Charging Valve.
1/8 BSPP Back entry with an O-Ring on the stem, 40mm Ø
Make sure that you remove the brass cross pin in the valve that holds the gauge in place before attempting to remove it.
On re-fitting, orient the gauge in the valve using only light hand pressure. If it will not come up vertical, then unwind up to one turn. The cross pin will hold the gauge in position once installed, and the O-Ring will hold the pressure.