Hydro Flask Standard Mouth Sport Cap

For one-handed, on-the-go hydration, add this Sport Cap to your favorite Hydro Flask bottle. The cap is insulated to keep your beverages ice cold for lasting refreshment through your morning hike or cycling route. The "no whistle" valve stays silent when opening, so there are no interruptions in your yoga class or studio workout. Compatible with all Hydro Flask Standard Mouth Bottles.