Allmax 9V Maximum Power Alkaline Batteries (48 Count) – 9 Volt

Customers find these 9V batteries to be excellent value, with one noting they're comparable to higher-priced name brands. The batteries perform well in various devices, including smoke detectors and LED lights, and are leak-proof. They receive positive feedback for their fit, with one customer mentioning they work perfectly in First Alert 9120B detectors. While some customers report they last a long time, others mention they only last about 4 months.