When using for a single battery filling requires squeeze bulb filler. Improve your battery life and performance with the Qwik-Fill Onboard battery watering system. Add water to your batteries without ever having to touch a battery or remove a cap! Qwik-Fill Onboard battery watering system lets you fill up to 3 batteries from a single fill tube, using a simple hand pump. Safer and more accurate than conventional filling, it installs in minutes without tools. Simply replace the existing battery caps with the Qwik-Fill manifolds and connect together with flexible tubing. The system automatically sends water only to low cells by using automatic shut-off valves at each cell, providing electrolyte level accuracy to 1/8". Makes maintaining proper electrolyte levels in hard-to-reach batteries easy, improving battery life and performance. Hand Pump (sold separately) works with any distilled water container (not included). Systems are reusable and can be installed on new batteries when old batteries are replaced.