Is there a difference between buying a brand Sto-Fen vs a knock off (probably a Sto-Fen clone) for my 580 EX II? I saw a cheap knock off for the 580 EX II (three heads, white, gold and blue) and costs half as much as a single Sto-Fen.





What would be a possible problem by using them? Melting perhaps to heat (rapid flash firing)?