SIZING: X Small 50 57cm 19.5 22 Small 50 57cm 22.5 23 Medium 50 57cm 23 24 Large 50 57cm 24.5 25.5 XLarge 50 57cm 25.5+ * The moisture wicking inner lining and antimicrobial treated foam and nylon elastane outer ensure a clean and safe product. Cross lace system in back with a fully adjustable chin strap.