The 
Nuprol Power 11.1v 2000mAh 15C Li-Ion Single Stick is a high-density airsoft battery designed for use in AEG replicas with standard buffer tubes or long battery compartments. As a Lithium-Ion (Li-Ion) battery, it offers higher capacity and a longer lifespan compared to traditional LiPo alternatives. 
Core Specifications
Chemistry: Lithium-Ion (Li-Ion).
Voltage: 11.1V (3-cell / 3S configuration).
Capacity: 2000mAh.
Discharge Rate: 15C Constant (30A) / 30C Burst (60A).
Connector: Deans (T-Connector).
Form Factor: Single Stick configuration.
Dimensions: Approximately 198mm x 20mm x 18mm.
Weight: Approximately 148g – 160g. 
Key Features & Maintenance
Energy Density: Offers roughly twice the charge cycles of a LiPo (up to 1,000 cycles) and has no "memory effect".
Safety Features: Includes an internal voltage protector to prevent the battery from dropping below a safe voltage.
Storage: Shipped at an optimal charge of ≥60% for immediate use or stable storage.
Charging Requirement: Must be charged using a dedicated Li-Ion Balance Charger; never use a NiMH or standard LiPo charger without a specific Li-Ion setting.