The Nash Siren R3+/R2/S5 Head Battery (CR2) is an essential battery for your Siren R3, R3+ and S5 bite alarms. With its optimal lifespan and superior performance over cheaper alternatives, this battery provides reliable and long-lasting power. Each package contains one battery, so you’ll always have a spare on hand. Whether you fish the waterfront at night or plan longer sessions, this battery is essential for reliable operation of your bite alarms.