The NP-40 is a replacement battery for Casio Exilim cameras. It features lithium ion chemistry that is free from memory effect, 3.6 volts, and 600 mAh power rating. Great as a backup battery.
Casio NP-20 Lithium Ion Rechargeable Battery for the Casio Digital Camera Replacement battery for the Casio EX-S1, M1, S2, M2 cameras Lithium ion chemistry free from memory effect ,3.6 volts ,600 mAh power rating Great as a backup battery .