That bit is legal - If anyone cares. Straight from the USEF.
Is this bit legal for 2011? The rules confuse me. They don't picture a bit of this type and refer to "rotating cheek pieces." I would call this a rotating mouthpiece. Don't know if that's semantics or if they only mean rotating on the other axis.
Proud owner of one Lunar acre! (Campanus Crater, The Moon)
So, does the bit stay flat and really not have any curb action at all? Is that the purpose of this bit with the revolving arms that look like they rotate freely up and down if you put pressure on them?
I have one of these bits and my horse loves it too. It certainly does have curb action, it just doesn't allow the port to rotate and put pressure on the horse's tongue. The arms still apply pressure to the curb groove via the curb chain and the poll via the head piece, just as normal.