Caveney Bottlenecks

 Here is a pair of Bottleneck handcuffs from the Caveney Invention Company from Oakland, CA circa 1910. 

These sold for $265 after 33 bids, with one key. 

Note this is the screw type key like a Darby, whereas the Marlin Daley bottleneck design uses a two pronged key. 

There are 3 heavy twist links and clevises but no swivel.