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    Rendezvu
    On a mission to get more people to enjoy the outdoors© 2026
    RendezvuAboutFor HostsFor BrandsFor Shoppers
    LegalTermsPrivacy
    ResourcesDocsContactFAQsFeedback
    CommunityInstagramLinkedInNewsletterCareers

    Brand: UltrAspire

    Category: Running Water Bottles & Flasks

    Recommended by Kilian Korth, Professional Trail Runner — Western Colorado

    Highlights: large capacity, soft flask

    The 800 mL SoftFlask with Locking Cap is a versatile hydration solution designed for active individuals. Its collapsible design and secure cap make it an essential companion for outdoor adventures, ensuring you stay hydrated without the bulk. 1. Holds up to 800 mL of liquid, providing ample hydration for extended activities. 2. Features a 42mm locking cap that prevents leaks and spills, ensuring safe transport. 3. Made from high-quality, PVC and BPA-free materials for a safe drinking experience. 4. Collapsible design allows for easy storage and portability when not in use. 5. Lightweight construction makes it ideal for runners, hikers, and outdoor enthusiasts. 6. Ergonomic shape fits comfortably in hand or in hydration packs for convenience. 7. Easy to clean and refill, making it perfect for both short outings and long excursions. This SoftFlask is perfect for athletes and outdoor enthusiasts who require reliable hydration during activities such as running, hiking, or biking. It performs best in dynamic environments where space is limited, and quick access to water is essential. Ideal for both casual users and seasoned adventurers, it excels in warm weather conditions and can be easily packed for travel or day trips.

    Price: $25.95

    Expert Review

    The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.

    Recommended by Kilian Korth

    Frequently asked questions

    What does Kilian Korth say about the 800 mL Softflask w/ Locking Cap?

    The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.

    Why does Kilian Korth recommend UltrAspire?

    Kilian Korth recommends the UltrAspire 800 mL Softflask w/ Locking Cap for running water bottles & flasks. The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.

    Is the 800 mL Softflask w/ Locking Cap a good running water bottles & flask?

    Yes — Kilian Korth recommends the 800 mL Softflask w/ Locking Cap by UltrAspire as their running water bottles & flasks pick. The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.

    More from Kilian Korth's Long Run / Race Kit

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    800 mL Softflask w/ Locking Cap by UltrAspire — recommended by Kilian Korth
    Nutrition & Hydration

    800 mL Softflask w/ Locking Cap

    Kilian Korth
    Kilian KorthRecommended in “Long Run / Race Kit”
    The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.
    Purchasing through this link directly supports Kilian
    Nutrition & Hydration

    800 mL Softflask w/ Locking Cap

    Kilian Korth
    Kilian KorthRecommended in “Long Run / Race Kit”
    The locking cap should be standard on all soft flasks. And the 800ml size allows you to use the Ultraspire Alpha vest and easily carry 2.4L of water without a bladder.
    Purchasing through this link directly supports Kilian
    800 mL Softflask w/ Locking Cap by UltrAspire — recommended by Kilian Korth
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    View Kilian Korth's expert gear recommendations on Rendezvu