This could be something for us older guys who may still have a Hasselblad or two lying around. I have an as-new Metz SCA 390 TTL flash adapter for sale.
It is used for connecting flashes compatible with the SCA 300 system to the Hasselblad 500 and 200 series cameras with TTL/OTF flash metering system. I used it attached to the accessory shoe on prism viewfinders on 553ELX bodies, but it can also attach to the flashgun bracket, or the accessory rail on the 500 series cameras.
Only the ungodly combination of the Swedes at Hasselblad and the Germans at Metz could possibly justify what used to be a horribly expensive little electronic gizmo like this - seriously they used to ask hundreds (yes Virginia - I said hundreds with an "S"...) for these things. I am beginning to feel faint just thinking about it!
$55 - includes FREE Priority Mail shipping within the Cont. US
-and NO added fees for PayPal or for using your Credit or Debit card