21 oz Standard Flex Cap
Product details
The Hydro Flask 21oz Standard Flex Cap bottle is your everyday hydration essential. With TempShield® double-wall vacuum insulation, it keeps drinks cold for 24 hours or hot for 12, ensuring refreshment all day. Built from durable stainless steel with a leakproof Flex Cap, this reusable and refillable bottle is cupholder compatible, dishwasher safe, and BPA-free. Pure taste, no flavor transfer, and a sleek, durable design make it perfect for work, workouts, travel, or play.
- 21oz Standard Mouth insulated bottle with Flex Cap
- TempShield® double-wall insulation keeps drinks cold 24h, hot 12h
- Leakproof when closed
- Made from durable stainless steel
- No flavor transfer, pure taste
- Fits most car cupholders
- BPA-free and dishwasher safe
- Not for use on stove, microwave, or freezer
21 oz Standard Flex Cap
Product details
Hydro Flask FAQ
Common questions about Hydro Flask
Learn more about what makes Hydro Flask unique.
What is TempShield insulation?
TempShield is Hydro Flask's double-wall vacuum insulation — it keeps cold drinks cold for up to 24 hours and hot drinks hot for up to 12 hours by eliminating heat transfer between the walls.
Which Hydro Flask size is right for me?
The 21 oz is ideal for short outings and fits most cupholders. The 32 oz is the all-day everyday choice. The 40 oz is best for long hikes, gym sessions, or anyone who needs to stay hydrated all day without refilling.
What makes Hydro Flask worth it?
Beyond the colour range, Hydro Flask pairs proven TempShield insulation with a durable powder-coat finish, a huge accessory ecosystem (straw lids, boots, slings), and a lifetime warranty — a stylish, leak-resistant bottle built to last for years.
Is Hydro Flask lead-free?
Yes — Hydro Flask has been proudly lead-free for over a decade, with no lead used anywhere in its construction, which is a deciding factor for many buyers comparing insulated bottles.
