Hydro Flask Slingback Bottle Pack Review (2 Weeks of Use 。In excellent used condition! The Slingback Bottle Pack holds up to a 32 oz Hydro Flask bottle plus all the essentials you need. Made with 100 % recycled polyester body, lining and strap material, the Slingback Bottle Pack is right at home on urban adventures, daily commutes and adventurous outings. Holds up to 32 oz Wide Mouth bottle Crafted of 100% recycled polyester Air Mesh, body fabric and ripstop lining Sling design rides close to your body for comfort and agility Two exterior pockets Interior padded tablet sleeve Two internal stash pockets Removable shoulder strap Stowable support strap