The HydroFlask Trail Series bottle is a lightweight and insulated stainless steel bottle designed for outdoor use. Here are the key features of the HydroFlask Trail Series bottle based on the search results:

1. Lightweight Design: The Trail Series bottle is 25% lighter than the standard HydroFlask bottles, making it easier to carry during outdoor activities .
2. Construction: The bottle is made from 18/8 grade stainless steel, which is known for its durability and resistance to rust and corrosion.
3. Insulation: The Trail Series bottle features TempShield insulation, which is designed to keep drinks cold for up to 24 hours and hot for up to 12 hours .
4. Perforated Strap: The bottle comes with a flexible perforated strap with aluminum pivots, designed for weight reduction .
5. Compatibility: The Trail Series bottles are compatible with most backcountry filters, allowing you to use them with different water sources .
6. BPA and Phthalate Free: The bottles are free from BPA (Bisphenol A) and Phthalates, ensuring that your drinks remain safe and free from harmful chemicals .
7. Size Options: The Trail Series bottle is available in two sizes: 24oz and 32oz .
8. Color Options: The bottle comes in three colors: clay, obsidian, and slate .
9. Lid Options: The Trail Series bottle is compatible with both the Coffee Flex Sip Lid and Wide Mouth Straw Lid, providing versatility in drinking options .
10. Warranty: The Trail Series bottle comes with Hydro Flask’s lifetime warranty against manufacturing faults, ensuring that you are covered in case of any issues .