The medium-sized aveoTSD fits 95 percent of patients. However, for the most accurate fit, order the aveoTSD Health Professional Patient Sizing Kit. This helpful in-office kit can be used to see which size aveoTSD is best for each individual patient. The aveoTSD Health Professional Patient Sizing Kit includes: One small, one medium and one large aveoTSD anti-snoring aid Two clip-on Uni-Spacers (4 mm and 7 mm) for extra titration One blue tray that can be autoclaved with individual pieces between appointments