The Envie NEXA ECR‑30 is a smart charger compatible with AA, AAA, and 9 V Ni‑MH and Ni‑Cd rechargeable batteries. It can simultaneously charge 2 or 4 AA/AAA cells or 1–2 nine‑volt batteries, automatically applying optimal charging current. The charger features BIS certification for safety and quality. Red LED indicators signal charging status for each slot; these remain lit even after reaching full charge. Built-in protections include reverse polarity, wrong insertion, constant current regulation, and no-charge detection for incorrect battery types—keeping devices safe and battery life optimized.