18th century province Zeeland, small silver and filigree work made in the city of Middelburg, often only a master's mark.

Well, this master's mark, not with certainty with question mark, perhaps
IDB with serif, in standing rectangle for Isaac du Booij. Isaac was on 20 August 1763 apprentice to Pieter B(r)eijdals. Isaac became registered silversmith, Middelburg in 1775. Died 10 March 1814 at the age of sixty.

Source; J. de Bree, Zeeuws zilver
Peter.