CamelBak: The name says it all: the Classic is the quintessential bike hydration pack, now updated with a Crux™ reservoir for a faster flow of water.PACK ONLY WEIGHT: 170g / 0 lb 5 ozTORSO FIT RANGE:38-53cm  / 15 - 21 inFABRIC:200D Polyester plain weaveFEATURES:• The brand new Crux delivers 20% more water per sip, with an ergonomic handle for easier refilling, and an on/off lever that makes it easy to prevent leaks.• Breathable air mesh back panel for a lightweight, comfortable fit.• Reflective accents for visibility in low-light environments.• Secure zippered pocket for essentials.• Lightweight, ventilated mesh harness.• External reservoir fill lets you refill your reservoir without removing it from the pack.