Olympus LI-42B Li-Ion Rechargeable Battery

From the Manufacturer
The extremely compact and ultra-slim design of the Li-40B rechargeable battery makes storage and transportation convenient. With a capacity of 660mAh, the new Li-Ion battery for the IR-300 and the slim FE-5500 allows hundreds of images to be shot before the battery needs to be recharged.
Product Description
OLYMPUS 202034 Olympus LI-42B Replacement Battery
Olympus Branded Retail Package
660 mAh capacity
Extremely compact and ultra-slim design
Allows hundreds of images to be shot before the battery needs to be recharged
Makes storage and transportation convenient