This adapter set allows you to quickly fill your hydration bladder with clean water without removing it from your pack. It is compatible with the Sawyer Squeeze Filter, the Micro Filter, and the Sawyer MINI Water Filter System (not included). Attach the Sawyer water filter to the adapters and squeeze water into your reservoir via the drinking tube. It is designed for use with industry standard 1/4-inch inner diameter drinking tube on most hydration reservoirs (hydration pack and filter sold separately).