This is a special customized flash, by Co van Ekeren for the twinned Sony P200 camera setup.
Note that there must be a connector on the twin setup for the flash. Van Ekeren made these setups both with and without option for flash photography.
This Metz Mecablitz 20 C-2 flash was altered by Van Ekeren with an added synchrobox, for perfect sync in flash photography.
Last picture shows the needed connector on the twin setup.