Evoke Callisto MIPS Wide Brim Helmet Color:Black Matte & Gunmetal Brown Quick Pebbled leather ITL01SBK MCL37 Brown Quick Pebbled leather especially for horses with sensitive mouths Helmet Shell Target Head Size Padding Thickness Fit Profile Small Shell 53 cm 9 mm Standard Fit 54 cm 6 mm Standard Fit 55 cm 4 mm Standard Fit 55 cm (Custom) 2 mm Custom (Looser Fit) Medium Shell 56 cm (Custom) 15 mm Custom (Max Snug) 56 cm (Custom) 12 mm Custom (Extra Snug) 56 cm 9 mm Standard Fit 57 cm 6 mm Standard Fit 58 cm 4 mm Standard Fit 58 cm (Custom) 2 mm Custom (Looser Fit) Large Shell 59 cm (Custom) 15 mm Custom (Max Snug) 59 cm (Custom) 12 mm Custom (Extra Snug) 59 cm 9 mm Standard Fit 60 cm 6 mm Standard Fit 61 cm 4 mm Standard Fit swap your standard liner for the Custom 2mm option