The SteriPEN Solar Charging Case uses the power of the sun to charge two CR123 batteries. Just orient the Solar Case towrd the sun. With an AC adapter, the case can charge the batteries using electricity. Connect jack to input located next to LED indicator. LED light indicates charge mode. Comes with Solar Charging Case, Adapter, (2) CR123 Rechargeable Batteries, Webbed Carrying Pouch, User Instructions. Features: Charges (2) CR123 Batteries for use with SteriPEN Adventurer or Traveler Handheld Water Purifier (sold seperately).Rugged case protects your SteriPEN Adventurer or Traveler.Portable.