The eggbutt is a fixed cheek bit, this may be useful for horses that are a bit unsure of the bit as it doesnt move around to much in the mouth, it should encourage the horse to stretch into the contact. An eggbutt bit would be less suitable if your horse is prone to leaning or taking hold of the bit
This mouthpiece has 2 joints, which means the pressure of the bit is distributed over both the tongue and bars of the mouth. Because the mouthpiece has two joints, it shouldnt cause any interference with the roof of the mouth. The Dr Bristol uses tongue pressure to encourage the horse to go on the bit, the flat shaped lozenge centre piece is set at an angle therefore causing a sharper, more pronounced pressure to the tongue, this bit will not encourage a true contact although may be useful if you need that extra bit of help in order to slow down or stop, it has bar and lip pressure but not a squeezing action like that of a bit with a single joint. The more joints a bit has the less likely the horse is to lean as the bit becomes more mobile.