What is this? Bell... Antwerp

[dsk]

https://www.finn.no/bap/forsale/ad.html?finnkode=232823127

Approx $29 not mine

[tubaman]

I was going to say 'dial blanks' until I saw that they are only 6.4cm diameter, which is too small for those.
Very curious?

[FABphones]

I would agree blanking plates, but not necessarily dial.

My collection still packed away, but if I can find an image will add. Meantime images of GPO #3 and GPO #4 blanking plates to show same style reverse.

[tubaman]

Could be dial blanks actually as I forgot the dial mount is a lot smaller than the finger wheel 

[countryman]

Possible but not the norm. Usually dial blanks do not have a completely flat front, but some kind of round structure.
Could be for office or PBX equipment also.

[HarrySmith]

I am thinking they are to cover the hole from a transmitter when a set is converted to a handset.

[Jim Stettler]

I am thinking they are to cover the hole from a transmitter when a set is converted to a handset.

I like  Harry's theory.
Are they the right size and configuration to fit a transmitter mount?
Jim

[dsk]

Newer seen an Antwerp phone modified from separate transmitter to handset.

[HowardPgh]

Newer seen an Antwerp phone modified from separate transmitter to handset.

Maybe that's why they are still in the box.