Ultraspire Zeta MBS Waist Belt & Pack with 8 oz Bottle Mesh pocket with quick access, reliable, magnet closure Lightweight construction, soft perimeter binding Inner flat pockets for a credit card, key, or smaller items Featherweight molded holster intuitively angles the bottle for a bounce-free ride Includes one 8 oz. bottle that hugs the body and features an angled shape for gravity-assisted flow Polarity System equipped which aid in the return and securing of the bottle Lined patent-pending Magnon Electrolyte Pocket to store your electrolytes and salt tablets Includes the MBS waist belt, which can be used with other interchangeable front and back pieces to create a variety of combinations. X-Small: 24-28; Small: 27-31; Medium: 30-32; Large: 32-37.5; X-Large: 36-42.5