Osprey&';s Quick Connect Kit seals off the reservoir, but can easily disconnect it from the hose for quick refills while leaving the hose in position on your pack. Also makes it easy to directly filter water into the reservoir in the backcountry. All parts are BPA-free, phthalate-free, lead-free, guaranteed. All materials are certified food safe according to FDA and EU regulations. Installs on any 1/4"/.635cm hose for easy disconnect/connect Bonus extra male piece and hose to connect to water filters