under my "flash system upgrade", d. H, buying a powerful manual flash unit and a remote control, I have procured the adapter to pack the Fensteuerungssender on the Sony A57!
Sits, fits and works 1a together with the system (manual control, without TTL). By locking the adapter holds good on the camera and can be disassembled easily!
All in all a good product.
Best wishes to the interested and gentle reader!
L. T.