Vintage 1950s Caramel German Snap Push Button Cuff Links on Foxed Cards

A card containing a pair of 
"Manschetten Druckknopf"
"Elegant and Practical"
"Mens Push Studs"
Easy Cuff Links in other words..
You just push the 2 halves together to do up your cuffs.
There have a mottled marble like pattern on celluloid.
A caramel colour, with lots of variations - each one is different.
They come on their original display cards which are a bit foxed.
Made by Prym - famous for making press-studs and other haberdashery items.
The price of £1 is for a card containing 2 pairs of studs