Cooper Island fanny pack takes the Cooper Island aura to the practical level. The sizing refers to the circumference of the pack waist band. Consider if you plan to wear over a jacket ( i.e. skiing) or just out on errands. I recommend ordering down a size if between dimensions ( see specs below). 

• 100% polyester

 • Fabric weight: 9.91 oz/yd² (336 g/m²)

 • Dimensions: 6.5″ (16 cm) in height, 13″ (33 cm) in length, and 2¾″ (7 cm) in diameter

 • Water-resistant material

 • Top zipper with 2 sliders

 • Small, customizable inner pocket without zipper

 • Silky lining, piped inside hems

 • 1¼'' wide adjustable straps with plastic strap regulators

 • S/M total circumference ( adjustable) 27.5" to 37.75 inches

 •M/ L total circumference ( adjustable) 35.5"- 52.5 inches

 • Blank product components sourced from China/ created in U.S.