What is the value

I have found by going through old family records, etc a pair of handcuffs owned by my father. He died back in 1977 and was in law enforcement back in around 1940, etc. They were made in the USA by the W.S Darley & Company - Chicago. I can't find a year. They are in a case and have the key? What would be an approximate value?
Thanks for your help.

The Darley cuffs are a bit unusual, but not rare. I would say a nice pair would sell for about $80-$100.

Joe