Hydro Flask insulated 21 oz Stainless Steel Water Bottle — Sandpiper with Leakproof Flex Cap for Everyday Cupholders

Hydro Flask's 21 oz Standard Mouth Sandpiper bottle is an insulated, leakproof stainless-steel water bottle built to keep drinks cold up to 24 hours and hot up to 12 while fitting cupholders and everyday routines.

This stainless-steel bottle combines TempShield® double-wall vacuum insulation with a comfortable flexible handle and a color-matched leakproof Flex Cap for a sleek, travel-ready thermos that resists odors and holds pure taste. At 21 ounces it’s sized to carry enough liquid for outings, workouts, or your commute while remaining compact enough for most backpacks and car cupholders.

How long will the Hydro Flask 21 oz keep my drinks cold or hot?

The ThermoShield double-wall vacuum insulation maintains cold beverages for up to 24 hours and warm liquids for up to 12 hours under normal use. This performance helps retain temperature without adding extra bulk or weight.

• Cold retention: up to 24 hours using TempShield® double-wall vacuum insulation.
• Hot retention: up to 12 hours for warm drinks.
• Lightweight construction that preserves temperature without heavy insulation mass.
• Designed not to transfer flavors between uses for consistent taste.

Is this bottle leakproof and practical for travel?

The included Flex Cap seals securely to prevent leaks when closed, and the bottle’s slim profile fits most cupholders for hands-free travel. The flexible handle makes it simple to grab, clip, or carry throughout the day.

• Leakproof Flex Cap when closed — throw it in a bag worry-free.
• Standard Mouth opening fits ice cubes and most lids in the Standard Mouth family.
• Cupholder-friendly diameter for cars, strollers, and bike cages.
• Durable stainless-steel exterior resists dents and everyday wear.

How should I clean and care for the Hydro Flask 21 oz?

The bottle and lid are dishwasher safe for easy cleanup, but hand washing is also quick and effective. Stainless steel construction prevents odor retention and flavor transfer, so your beverages taste fresh each time.

• Dishwasher safe parts — bottle and lid can go in the dishwasher.
• Hand-wash friendly for quick rinses and deeper scrubs when needed.
• BPA-free stainless steel that won’t hold onto smells or flavors.
• Not suitable for microwave, stove, or freezer use; avoid exposing to open flame or extreme direct heat.

Which lids, accessories, and uses are compatible with this Standard Mouth bottle?

The 21 oz uses the Hydro Flask Standard Mouth system, so it accepts a variety of caps and accessories to match your routine — from straws to sport caps. The color-matched cap gives a coordinated look while other caps add different sipping styles.

• Compatible with all Hydro Flask Standard Mouth caps and lids, including Flex Straw Cap.
• Swap lids for sport-friendly drinking, filtered options, or insulated travel caps.
• Versatile for hiking, gym sessions, desk use, commuting, and travel.
• Monochrome Sandpiper finish provides a stylish, unified appearance.

Who is this for: The Hydro Flask 21 oz Sandpiper bottle suits anyone wanting reliable temperature control in a mid-sized bottle — commuters, students, gym-goers, and outdoor enthusiasts who need a leakproof, cupholder-friendly bottle that preserves taste and color. If you want a durable, easy-to-clean stainless-steel bottle with flexible carrying and broad lid compatibility, this Standard Mouth Hydro Flask is built for everyday use.