The Dr. Bristol is a double jointed bit, with the link in the middle being rectangular in shape and having
distinct edges – it is held at an angle against the tongue, and when pressure is
applied to the reins it creates a sharp pressure on the tongue, pulling the
horse up sharply. It can cause severe bruising to the tongue.
Conversely, the french link, also a double jointed bit, has the middle link
rounded off and soft. It is in a semi-figure of eight shape, smooth edged, and
is held flat against the tongue, not at an angle. It works by breaking the
"Nutcracker" action, stopping the squeeze on the bars and the pressure on the
roof of the mouth. It is an excellent bit for most disciplines, and most horses
take to it very well indeed. It provides the perfect balance between "play" and
preciseness, encouraging salivation while not distracting the horse. Most horses
will never need any other bit.