Make it easier to bring along your standard Hydro Flask, whether you're seeking the peak or starting your morning commute. The new Flex Cap offers a solution with its flexible strap, sturdy steel pivots, and Honeycomb Insulation(TM) to control your beverage's temperature. Just push it into your water bottle's opening, grab it, and begin your journey. Made with recyclable PP#5. Includes a flexible TPU strap, stainless steel pivots, and Honeycomb(TM) insulation. Honeycomb Insulation(TM) inside lid offers better temperature control. Fits standard Hydro Flask water bottles. Free of BPA, phthalates, and toxins. Built to last. 1.91 in. mouth diameter. Weighs 2.5 oz. Lifetime warranty. | Hydro Flask Standard Mouth Flex Cap