This is an E-Flite 11.1 Volt 800mAh 3-Cell Li-Po Battery for the Blade CP and CP Pro helicopters.  Having extra batteries charged and ready to go when out flying is a great way to keep you in the air.  These are high-quality, genuine E-Flite packs that are designed to work with your Blade heli.

Type: Lithium Polymer (Li-Po)
Capacity: 800mAh
Voltage: 11.1V (nominal)
Connector Type: JST (BEC) for discharge; E-flite Balance Connector for balance charging (Use EFLC3105 Balance Charger only)
Wire Gauge: 20GA
Number of Cells: 3 series
Weight: 2.3 oz
Dimensions (WxLxH): .95 x 2.75 x .70
Application: E-flite Blade CP Pro (EFLH1300)
Maximum Continuous Discharge : 10C
Maximum Burst Discharge : 12.5C
Maximum Continuous Current : 8A
Charge Protection Circuitry: Yes, via E-flite Balance Connector only (Use EFLC3105 Balance Charger)