Dear friends,  I am sorry to have to announce that there never was
a typical organ grinders cap in the Netherlands. In the thirties and
forties of the 20th century many people in the Netherlands were
wearing caps (sing.: pet, plural: petten), but they were not typical
for organ grinders.  This model is, of course, way out of fashion, so
they may be difficult to obtain these caps even in the Netherlands.
I know of some English caps which come very near to this model, so
maybe they can be ordered there.

Hans van Oost, KDV, Netherlands

P.S.  Thank you for sending MMD again!  I missed you!