Fabulous
This solves quite a few questions about the origins of these simulated chevrons.
There are a few different types but I believe they were likely made by the same maker like #493 and the ones on strand #495 in our chevron book.
The large round are 30mm, hollow and light with a thin layer of 2 to 3mm.
The smaller round are 20 to 22m and are not hollow.
The cylindrical shape 30 x 23mm are also not hollow with a large ~ 8mm hole
#493 is a massive 50 x 36mm with large hole and was collected by Michael Heide in the 60s.
We have a bead in the Museum like #27030 in medium size that I had not been able to identify, Thanks again for showing this card.
JP