Eley pneumatic rimfire cartridge primer

[reccetrooper]

Can anyone make sense of this item that is in today’s Cowans auction in the USA?

Is it what they describe it as?
How does it work?
Why does it say Eley / Essex above Devonshire England?

https://www.cowanauctions.com/lot/eley-pneumatic-rimfire-cartidge-primer-3075425

 

[2pounder]

my guess would be for loading larger calibre rimfire early cartridges, not .22.

 

[Dutch]

I have tried to figure out how this thing works.
Could somebody help please?

Rgds

 

[John Kindred]

What material are these things made from.? The photo appears to be at least part plastic, which would almost certainly rule out anything to do with large rimfire rounds.