Nathan Soft Flask with ExoSpine Hydration Flask

For runners who need clean, reliable hydration on long efforts or race day, the Soft Flask with ExoSpine is our pick for vest-based hydration setups. ExoSpine ribbing keeps the flask from collapsing as it empties, so you get consistent flow without fighting the squeeze. Rolls up tight when dry, so you're not hauling dead weight late in a run.

• ExoSpine ribbing prevents mid-squeeze collapse, giving you consistent, easy flow even when the flask is running low
• 14oz capacity works as a primary flask for short-to-mid efforts or a secondary flask in a full hydration vest setup
• Soft TPU construction conforms to vest pockets and stays low-profile during high-output running — no sloshing, minimal bounce
• Compatible with Nathan speed vests and most standard hydration vest flask pockets; also works as a standalone handheld
• Rolls up compact when empty so you're not wasting pocket space or carrying unnecessary weight when running light