Duracell Specialty alkaline MN21 batteries – long lasting power for your devices. Duracell Specialty batteries have up to 5 years of in-storage guarantee with Duralock Power Preserve technology so you can be confident these alkaline batteries will be ready when you need them. They are designed for use in Wireless remote controls, wireless doorbells, security systems (alarms, locators). Also known as 23A, 23GA, A23, E23A, GP-23A, GP23A, K23A, L1028, LR23A, LRVO8, 8LR932,Duracell MN21, MS21, V23, V23GA, VR22 and a 8F10R.