This is a Wessex Music solid silver flute headjoint with a Robert Bigio stopper and zirconium crown already fitted.
These headjoints were custom-specified to order by Wessex (similar branded headjoints can be well over £1000) and can dramatically improve your flute's sound. For details of the Bigio crown and stopper see http://www.bigio.com/stoppersandcrowns.htm
Outside diameter of the joint is approx. 19.8mm - you may need to have this fitted to your flute by a repairer.
New item.
Any questions just ask.
Ref #1