LED indicator: Two LED indicators show the charging process of its corresponding slots but will not turn off once fully charged- OPTIMIZED MULTI-BATTERY CHARGING SYSTEM: Designed for a broad spectrum of Ni-Cd and Ni-MH rechargeable cell sizes, this battery charger comes with LED indicator that shows the charging status of its corresponding slots.- AUTOMATIC CURRENT SELECTION: Compatible with 2-4 AA/AAA Ni-MH/ Ni-Cd types rechargeable batteries this charger automatically selects the charging mode based on battery type and capacity.- HIGH-END SAFETY: This charger is BIS certified which means it provides guarantee of quality, safety and reliability of the product. Integrated high-performance protected circuit automatically short-circuiting.- SUPPORTS INPUT: 220V AC, 50Hz , SUPPORTS OUTPUT: AA/AAA 2.4V DC 240mA , AA20Max2 AA20Max4 , AAA 120mAx2 AAA 120mAx4. It works best with Envie batteries