This set of Inline Adapters for Screw-on Filters turns your Sawyer screw-on/off filter into an inline filtration system for your hydration pack with this simple accessory. Just screw the connections onto the each side of Sawyer Squeeze filter and insert the filter inline into your hydration pack drink tube (sold separately). With the filter installed this way, you can fill your reservoir with dirty water and drink safe water from the tube. When you don't need to filter water, unscrew the connections from the filter and simply screw them together to reconnect the tube just remember to thoroughly clean a dirty reservoir before drinking from it without your Sawyer Filter. Designed for use with industry standard 1/4-inch inner diameter tubing, it's compatible with the Sawyer Squeeze Filter. Since 1984, Sawyer has used technological advancements to create products that keep you outdoors from the backcountry to the backyard including insect repellents for both skin and clothing, water filters for camping and emergencies, and sun protection.