We selected Lithium Iron Phosphate (LifePO 4) type of batteries for it’s advantages in safety properties and Long service life. LifePO4 is thermally and chemically stable, reliable without the possibility of lithium fires. LifePO4 batteries have long service life, with a shelf life that far exceeds the service life of many other batteries. Lithium Iron Phosphate (LifePo4) batteries are “NOT” Lithium Polymer (LiPO, LIP, or Li-Poly) batteries. Not only we enclosed the Batteries in a metal cage, we added many Battery Protection circuits – Over Voltage protection, Thermal Shutdown, Over Charge protection, Over Drain protection. The LifePO4 batteries are used in our products are UL safety approved and MSDS certified.