A single 9V battery that lasts up to 5 years in storage and comes with advanced leak-proof technology. Alkaline battery 4 pack 100% Life Guaranteed* Suitable for a range of devices Leakage prevention technology - superior nylon top closure Last up to 5 years in ambient storage Size: AA Single pack *Commercial guarantee vs. the Minimum Average Duration across 2015 IEC 9V battery tests. Results may vary by device or usage pattern (www.iec.ch)