Trumpy:
The 'device' you see is actually one of many configirations that were readily available many years ago.
Common to see in old residential, they were used with 'zip cord' (2-wire lamp cord) to install receptacles along the baseboards. Some had screw terminals for connections, others had a piercing setup.
A basic source of fire potential, and most were a DIY install, although some of the 'old timers' may have installed it.
Mfg that I remember were 'Eagle' & 'Leviton'.
Harold must have seen this also.
They still make and sell these. I have as large array of them for my Christmas display...
