Designed for speed and the female runner who wants a lightweight, minimalist pack, the Nathan VaporMag 2.5L Hydration Vest features ventilated mesh material which provides a highly breathable feel while keeping the weight low. Quick-sip flask system includes two 12 fl. oz. BPA-free ExoShot soft flasks; extended straw tubes allow easy sipping without removing them from the front pocketsFront adjustable sternum straps dial in the fit and comfort for a bounce-free ride4 front pockets accommodate the included soft flasks, nutrition, smartphone and essentialsWomen-specific design fits like clothing with lightweight mesh and moisture-wicking materials, making this vest a great choice for comfort on the move and a bounce-free rideFront pocket sized to fit smartphones up to the size of an iPhoneA(R) 8+; water-resistant pocket lining helps protect your phoneUpper back pocket is compatible with a 1.5-liter hydration reservoir (sold separately)Accessible lower back stash pockets can hold a jacket, layers or an extra bottleLower back zippered pockets secure additional running essentialsReflective hits help you stay visible to motorists in low lightCapacity: 2.5L/153 cubic inchesSizing: S: 30 - 31 inchesM: 32 - 33 inchesL: 34 - 35 inches