This is the Spektrum 4000mAh 2S 7.4V Smart LiPo receiver battery with IC3 plug.

• Spektrum Smart Technology Makes Charging and Maintaining Batteries Easy
• Integrated Microchip Stores Unique Parameters for Each Battery
• IC3 and IC5 Connectors are Compatible with EC3 and EC5
• Save Time and Hassle, while Improving Battery Life
• Smart Discharge Allows Batteries to Automatically Discharge to a Safe Voltage
• Includes standard servo connector discharge lead for added convenience
• User Assignable Smart Discharge Allows Batteries to Automatically Discharge to a Safe Voltage