Simple, ergonomic, efficient and adjustable, the Sync Hydration Belt makes one-handed refueling a snap. A simple flip of the wrist and the bottle is free from the bracket. Snap it back with secure engagement and your hands are free. Easy to use and adjustable, the Sync Hydration Belt takes race-day and training refueling to the next level. Size Chart XS - 25-28" (71cm) S - 28-31" (78cm) M - 31-34" (86cm) L - 34-37" (94cm) XL - 37-40" (101cm)