The Swales Pelham is designed to give control specifically for strong horses that are inclined to lean down. It is extremely popular bit with the showing and driving fraternity and is often used in other disciplines for faster work on an experienced horse that is "over enthusiastic".
This is the only Pelham that removes poll pressure as the cheeks are attached to the inner rings. That emphasis the action on the curb and exerts more pressure on the jaws causing the lifting action.
The Happy Tongue Straight is a solid mouth bit which is ported to relieve tongue pressure but is not curved. This makes it slightly harsher than the curved Happy Tongue. The Happy Tongue Straight complies with FEI requirements.