Can anyone tell more more about these hiatts?

Good afternoon everyone,
I'm new here and just starting a little collection, I've recently acquired these pair of hiatts
Chain handcuffs, they have no other markings except for "hiatt" stamped on them.

Can anyone tell me a little more about these?age etc?

Any information would be much appreciated.

Thanks

For some reason I can't upload the picture- here's the link below-

I believe it is a 1980 aluminum cuff -UK made.

Damon