AMCO Compatible Replacement Battery For LifePak 500 Non-Rechargeable Lithium (LiSO2), 12V, 7.5ah A long-life low-maintenance battery pack designed for low or infrequent use environments. The Physio-Control LifePak 500's operate on batteries only.  Always have a fully charged spare. It's good insurance!

Batteries ship with a minimum of 2 year shelf-life.