COMPATIBILITY: Designed exclusively for HydraPak 42mm Bite Valve Caps, HydraPak SoftFlasks, HydraPak UltraFlasks (2023 or newer), this product is not compatible with Salomon flasks, other caps, or other products. EASY DRINKING: The Run Straw softflask accessory extends the reach of your flask for easier drinking while on the move. TO USE: Remove bite valve from cap and insert drink tube into hole. TO REMOVE: Unscrew cap to access base of straw, pinch the bottom of the straw and pull out from the top. LEAK-PROOF: Bite valve auto-seals after each sip, eliminating annoying drips or leaks when not drinking. BEYOND LIFETIME WARRANTY: If you experience any issue, we’ll repair or replace the item for free. Whatever it takes to keep your adventure going.