These hooks are zinc plated and have a baseplate approx 50mm x 50mm with four 7.3mm mounting holes.
Base plate is 4.5mm thick (approx) and the hook approx 7.6mm in diameter.
The hook is welded to the baseplate (not pressed ! ).
Minimum opening of hook is approx 8.5mm.
See article on stay wire supported installations.
Also see :
3 and 4 hook collars