The 
Nuprol Power 7.4v 1300mAh 20C LiPo Battery with a Deans/T-connector is a popular, compact lithium polymer battery primarily used for airsoft guns and RC hobbies. It offers high performance and is designed as a slim "stick" configuration to fit into tight battery compartments. 
 
Key Specifications
According to information from the official Nuprol website and various retailers, the specifications are as follows:
Chemistry: LiPo - Lithium Polymer
Capacity: 1300mAh
Voltage (Cell Count): 7.4V (2S)
Constant Discharge Rate: 20C (equivalent to 26A)
Burst Discharge Rate: 40C (equivalent to 52A)
Connector: Deans / T-Connector
Balance Connector: JST-XH
Configuration: Stick
Weight: 95g
Dimensions: 13 x 23 x 128 mm 
 
 
User Reviews and Features
Reviewers and experts note the battery's compact size and reliable power delivery. 
Compact size: The slim profile is frequently highlighted as ideal for replicas where space is limited, such as in certain airsoft guns' buffer tubes.
Performance: Users report snappy trigger response and consistent power delivery without significant voltage sag.
Quality: The batteries are manufactured in an ISO 9000 quality control accredited facility and use premium leads and cells.
Safety: Reviewers and retailers strongly emphasize the need to use a LiPo balance charger only and to store/charge the battery in a LiPo safety bag to prevent fire hazards.