Olympus BLN-1, BCN-1 Battery (2-Pack) and Charger by Wasabi Power
File:OM2Spot battery mod (5476863878).jpg - Wikimedia Commons
Amazon.com : Kastar 2-Pack Rechargeable Battery Replacement for Olympus BLN-1 BLN1 Battery, BCN-1 BCN1 Charger, Olympus M-D E-M1, OM-D E-M5, OM-D E-M5 Mark II, OM-D E-M5 Mark III, Pen E-P5, Pen-F Cameras :
Kastar AC Wall Battery Charger Replacement for Olympus OM SYSTEM BLX-1 Lithium-Ion Battery, Olympus OM System BCX-1 Battery Charger, Olympus OM System OM-1 Mirrorless Camera - Walmart.com