From mountain trails to morning yoga class, The Standard Mouth Insulated Sport Cap lets you hydrate one-handed and on the fly. It’s the first insulated sport cap specifically designed to keep water in your Hydro Flask bottle ice cold, sip after sip.

Please note: This lid is not leak proof.

• Compatible with all Standard Mouth bottles
• Insulated for enhanced temperature protection
• Quiet, "no whistle" valve
• BPA-Free and Phthalate-Free