Nathan Fire and Ice Flask (2-Pack) First ever double-wall insulated flask in 8 oz./235 ml flasks Easy squeeze, double walled hydration flask with hi-flow/race cap is dishwasher safe Integrated, never wear reflective fabric offers 360 degree reflectivity for optimum visibility at night Comfort grip allows for fast access Fits all 10 oz. Nathan hydration belt SpeedFit holsters and the QuickShot Plus insulated handheld