The Billy Allen snaffle fills an important gap in transition training. The center roller covers the hinge, stiffening the mouthpiece and calming the typical hinge snaffle nervous horse. The "Sweet Iron" mouth is designed to rust creating a sweet pleasant taste. Copper bars are designed keep the mouth moist and responsive.
The sweet iron material, when exposed to saliva/moisture and oxygen creates a surface layer of oxidization - rust - which is what gives the sweet feeling in the horses mouth, encouraging salivation.
Its totally harmless to your horse and there is no need to scrub it off, just a quick wipe with a clean cloth after a ride will keep your bit in tip top shape.
Sweet iron is a nice warm metal in the horses mouth that heats up to body temperature very quickly, encourages salivation and bit acceptance through the flavor. It can become rough with age, but a light sand with some superfine wet/dry sand paper can restore the smooth surface.
5" Mouth, 2 3/4" Blue Steel Dees.