These collars were widely used, from the 1920s to the 1960s, by men and women.
They would have been worn with matching shirts, as part of a company uniform, or else for leisure wear with a matching or contrasting shirt.
These collars are unused, and in very good condition.
There is no garment composition indicated, but it appears to be cotton.
Difficult to date, but I would GUESS probably 1950s to 1960s.