Using this Sanyo Sub - C NiCd rechargeable battery is easy. Just insert it into your device following the correct polarity. When charging, use a suitable charger designed for NiCd batteries to ensure a fast and safe charge. As for maintenance, avoid overcharging the battery as it can reduce its lifespan. Also, don't expose the battery to extreme temperatures, like very hot or cold environments. If you don't use the battery for a long time, store it in a cool and dry place. Keep the battery clean and check it regularly for any signs of damage. If you notice any problems, replace the battery right away to keep your device working well.