The loose rings snaffles make a more mobile bit than an eggbutt or fixed cheek bit, which should encourage your horse to keep a relaxed jaw and mouth the bit. The loose ring may be useful if your horse leans on the bit, or takes hold, as the bit is always movable so the horse cannot take hold as easily as they could with a fixed cheek. This bit is also useful for gaining contact as the movable mouthpiece enables the bit to fit the mouth, contour the tongues natural position and sit comfortably.
Single Jointed Bits
The single joint puts pressure on the sides of the tongue, on the lips and on the bars due to the nutcracker. The single jointed bits also may have a head raising action so would be less suitable for your horse if they ride with a high head carriage or above the bit. Also breeds such as Irish Draughts, may have particularly large tongues, therefore having less room in the mouth for a single jointed bit as this pushes the bit nearer the roof of the mouth, also Arabs and alike may have a low palate, both of these examples may not benefit from the single jointed bits as the nutcracker action may cause brushing of the roof of the mouth. This Magennis Mouthpiece
The Magennis has small copper rollers set into the mouth piece, which are designed to roll over the jaw to help prevent a horse from crossing and setting its jaw, the copper in the rollers is renown for causing salivation and helping the horse mouth the bit.