This is a Redcat USB Ni-MH 600ma Charger.
 
Features:
MCU cut-off function
Over-current/over-voltage/over-heated protection
Output reversed connect protection
Specifications:
Input: min. 5V 1.5A
Output: Max. 600mA/5W
Support: 5-7S NiMH
Static Green LED: stand by or finish charging
Static Red LED: charging
Flash Red LED: Error 
Length of output wire: 30cm
Output port: Banana