Hello,
I also assume that the ebay offer shows Star tension screws. These screws have tiny differences to other screws: the 'ring' below the square head is thicker and has no rounded edges and the square head itself is looking more angular than at other screws.
quote (out of the link, a special note to Star screws)
This is a special M5 screw used on some old Japanese Drums (Star, Drummate etc..)
Diameter about 4,9 mm and one thread is 0,9 mm high 28 thread per inch
unquote
Just for the reference here.
Cheers, Ralf