Hydro Flask Lightweight Standard-Mouth Vacuum Water Bottle - 21 fl. oz.

Members save 20% on this item with code MEMBER23 through March 27. Terms & conditions
Color: Obsidian
Choose a shipping method

Members get an estimated $4.00 back on this item as a part of your annual .

Members get an estimated $4.00 back on this item.
To buy,  sign in as an REI Co-op Member or join now.

Delivering ice-cold refreshment for your adventures—without extra weight—the Hydro Flask Trail Series Lightweight wide-mouth vacuum water bottle is built for long treks and spontaneous route changes.

  • Features

    • 25% lighter than the original 21 fl. oz. Hydro Flask standard-mouth bottle, thanks to thinner 18/8 pro-grade stainless-steel walls
    • Tapered walls are thinner up top to save weight, and thicker on the bottom for durability
    • Standard mouth opening is ideal for quick sips on the trail; plus, the slim bottle profile stashes easily into a pack pocket
    • Honeycomb-insulated standard-mouth cap is leakproof and features a flexible perforated strap and aluminum pivots to cut weight
    • TempShield® double-wall vacuum insulation keeps beverages cold for up to 24 hrs. and hot up to 12 hrs.
    • Free of BPA and phthalates


    View all Hydro Flask Water Bottles
  • Technical Specs

    Best Use


    Liquid Capacity (L)

    0.6 liters

    Liquid Capacity (fl. oz.)

    21 fluid ounce


    2.8 x 10.2 inches

    Fits In Cup Holder


    Water Bottle Material

    Stainless Steel


    Stainless steel

    BPA Free




    Bottle Opening


    Cap Type

    Screw Cap


    9.6 ounces

  • Reviews
    92 reviews with an average rating of 4.6 out of 5 stars

    Loading Reviews...
  • Questions & Answers

    Loading Questions...