Wide Mouth Flex Cap by Polerce (Black) - Compatible with all Wide Mouth bottles (Hydroflask, Yeti, etc) - BPA Free Sip it straight from the Bottle! Our durable Flex Cap lets you add perfect sipping to all your outdoor adventures. It works with all Polerce bottles, and, thanks to the flex strap, you can hold your Polerce Bottle easily. It is compatible with any wide mouth bottle (Hydroflask, Yeti, etc). It has a convenient finger loop for easy carrying and easy twist off for sipping straight out of the bottle. The lids are 100% leak-proof, BPA-Free, and have a lifetime warranty. Combine the lid with our Stainless-Steel Double Wall, Thermally Insulated Flask. The double wall vacuum insulation makes the Polerce Bottle sweat-free! It keeps your drink COLD for at least 24 hours, and HOT for at least 12 hours. Premium Double Wall Stainless Steel - Polerce Bottles are made of 18/8 Stainless Steel. This quality stainless steel will ensure that your bottle lasts a lifetime and will never leave a metal taste or rust. The bottles just like the lids are 100% BPA-Free and Non-Toxic.