JustDressageIt, what I should have said is the Baucher has a fixed purchase on the bit. The purchase being the part of a bit that extends above the mouth piece like on a Western type curb bit or Pelham, I.e. With the Baucher there is slight poll pressure when the horse has bit contact or on the bit.
I used the Baucher with my QH mare when I decided to try going in a Dressage saddle and snaffle bridle with her. As an 8 year old when we became each others she had always been ridden Western and with a tiedown. The first time I tried riding her without the tiedown she flung her head until I could see the tip of her nose.
After trying 4 other snaffles on her I found the Baucher. It worked like a charm with her.