Trust Pony Loose ring Sweet Iron Locked | 12mm

Sweet iron bits give off a sweet taste through contact with saliva which naturally stimulates the horse's salivation. Because of this property, you see that horses will generally accept a sweet iron bit faster and better.

A water snaffle has movable bit rings and is therefore somewhat looser in the mouth. 

A Trust locked bit is similar to a single jointed bit but cannot hinge as much and blocks when there is more rein pressure, turning the bit into a bar. Locked bits are suitable for horses that walk through the hand and are not suitable for an inexperienced rider.