I am very lucky that the previous owner of my new horse is letting me borrow all of her tack until I get my own. One of the last thing I need is his dressage bit. I was told it was a Herm Sprenger Dynamic RS eggbutt, but I ordered that bit and it isn't quite the same. The bean on the dynamic RS seems to have a bit more an angle, and it's thicker, especially at the base (near the cheekpiece). Pictures online don't really show the difference between the herm sprenger styles, so I"m hoping you guys can help. I have pictures, but they didn't turn out great, and I don't have anyway to share them. If any of you guys are premium members, would you post the pictures if I email them to you?
There is the KK Eggbutt (thicker and with a true eggbutt ring) and the HS Dynamic RS D-Ring ... which looks like it is a hybrid in that the D-Ring looks almost like an eggbutt. The mouthpiece is a french link and more curved and slightly thinner (very nice bit).
Go to the Dressge Extensions website and compare the KK Eggbutt to the Herm Sprenger Dynamic RS D-Ring.