RS 312 – RS Electrical Single Way Portable AC/DC Aquarium Battery Air Pump (commonly sold as model R-212) is a portable, battery-powered air pump designed to supply oxygen to aquarium water where mains power isn’t available. It runs on 2×1.5 V batteries, delivers a steady airflow (~60 L/hour) to keep your fish and aquatic life healthy, and includes an air tube and airstone for easy setup. Lightweight and compact, it’s ideal for small freshwater tanks, travel use, or power outage backup aeration.