Wein Products W990560 (SSHSHS) Safe-Sync Hot Shoe To Hot Shoe,Black

Does it work with Nikon 7000 and 750

does it provide a signal to the e-ttl contacts on a Canon D550 to fool it into just triggering the flash without trying to set time and light?

Can this be used to protect my sony a7r3 and Nikon 810 from my speedatron d802d flash pack?

I have a Sunpak Auto 36DX Thyristor flash and a 4000AF power zoom flash. I wish to use them with my Nikon D80 and D90. Will this gadget allow that?