COAST Z550 ZITHION(TM) Li-Ion non-ported rechargeable batteries are designed to be charged from inside your COAST light. COAST ZITHION(TM) batteries saves you money on batteries, while providing you a no-hassle power solution. With a reduction of lighting components, these batteries also tend to be lighter in weight, without sacrificing COAST's Trusted Tough power.All COAST ZITHION(TM) batteries are protected with premium overcharge/discharge protection and are backed by COAST'S one-year warranty.