Rare Disk Music Box Playing Postcards

We have never seen anything like these music box playing postcards before. I would love some more information about these postcards. Does anyone know what type of machine they would have played on? The small square die cut holes are not damaged at all and if one had the right machine they would certainly still play. I have included descriptions for each one below.

Rare Music Box Playing Postcard, Prague pub. Ser. II Type 4, “Na tom Prazskem moste-”, Great Card! UB VF









Rare Music Box Playing Postcard, Prague pub. Ser. II Type 4A, “Na tom, Prazskem Moste-”, Great Card! UB VF









Rare Music Box Playing Postcard, Prague pub. Ser. II Type 5A, “Zwei Sternlein am himmel --”, Great Card! UB VF









Rare Music Box Playing Postcard, Prague pub. Ser. III Type 7, “Svaty Vaclave -”, Great Card! UB VF