Stainless steel base - ensuring the longevity  EquiKind+ coating - to create a thinner mouth piece then rubber bitsMouth Piece Thickness: 15mmThis creates a more warming mouth piece, making it a favourite for sensitive mouthed horses who dislike the chill from metal bits. The EquiKind+ coating also makes it perfect for horses who do not have a lot of room for a thicker mouthpiece.Mouthpiece Length & Cheek Height:4.5” & 135mm5” & 135mm5.5” & 135mm