The Steri Pen Solar Charging Case can charge one rechargeable double-cell (7.2V) lithium battery or two single cell RCR123 batteries. The case will house either the Adventurer or any silver-colored Traveler or Traveler mini model & also has a spot for 2 CR123 Rechargeable batteries. Solar Power Use the power of the sun to charge your Steri PENS rechargeable battery. Just orient the Solar Case toward the sun Mains Power Use electricity for a faster charge. Plug in the AC adapter, connect the jack to the input next to the LED indicator. LED light indicates charge mode. * Important*: ONLY put rechargeable CR123 batteries in your Solar Charging Case. Putting NON-rechargeable batteries in your Solar Charging Case could result in damage to the Solar Charging Case and/or batteries; in rare instances it could result in fire.