This light weight, pack utilizes the AdaptiveFit system to conform to the runner! The VaporAir’s little brother has a game changing fit and contours to your form, regardless of change to your shape or size. With the lightweight, breathable and chafe-free material, you can rest assured that when you gear up for your next marathon, trail run, hike or Spartan Race, you have all the hydration and storage for on the go that you need. Comfort Fit The adjustable sizing system on the Vaporswift 4 Liter Men's Race Vest is the perfect tailored, body mapped fit for all men's body types. The vest fit is snug and overall sizing can run small so it is recommended to size up! Peak Performance With the lightweight, chafe-free and breathable materials, this bounce free vest can store all of your running essentials with different storage pockets. Stay hydrated with the 1.5L bladder and side storage pockets that can fit more bottles! Features: Adjustable Sizing System Vest fit is snug and sizing tends to run small - size up! Includes 1.5L bladder and its quick release valve system Two storage pockets on the side (can fit flasks up to 22oz) Large main storage compartment One back kangaroo pocket for essentials and more Lightweight and comfortable No bounce, chafe-free breathable materials Secure front shoulder zippered pockets 360 degree reflective for runs in low visibility Transparent zippered pocket for quick viewing 20% Nylon, 80% Polyester FIT: Adaptive Storage Capacity: 244 cu in / 4 Liters Weight with Bladder: 10.68 oz / 302.9 g Weight without Bladder: 6.87 oz / 194.9 g Wash and Care: Hand wash cold Use mild detergent (try our PowerWash) Line dry Do not use bleach Do not use fabric softener Do not iron or dry clean