Safety Warning: Never use or charge the battery that has ballooned or swelled, leaks, overheat or anything else abnormal occurs. Never disassemble, puncture, shock or crash the lipo battery. Never put the battery into fire. Put the battery or pack at a safe place where infants or kids can not reach. Never overcharge the battery, improper use, such as short circuit or overcharge might cause explosion or fire. Compare the Cell Size with your original old battery pack Designed to meet or exceed performance of original battery. Tested by manufacturer to match the OEM products. Over-voltage, over-current, over-charge, and short-circuit protection. A good choice to replace of the old 4.8V 700mah Ni-Cd battery and update the running time. Will provide 3 times working time than your original 4.