The 
Nuprol Power LiFe Battery Slim Stick 1100mAh 9.9v 20c
 is a lithium iron phosphate (LiFe) battery designed for airsoft replicas, offering a higher rate of fire and longer life cycle than traditional NiMh or LiPo batteries. It features a stick configuration and a mini Tamiya connector. 
 
Product Specifications
Attribute 
Detail
Chemistry
LiFe (Lithium Iron Phosphate)
Voltage
9.9V
Capacity
1100mAh
Configuration
Stick (Slim)
Discharge Rate
20C constant / 40C burst
Connector
Mini Tamiya
Balance Connector
JST-XH
Dimensions
Approx. 16 x 20 x 128mm
Weight
Approx. 115g
 
 
Key Features & User Opinion
Higher Performance: This battery provides a higher voltage and rate of fire compared to standard NiMh batteries, as noted by sources like Patrol Base.
Safety & Durability: LiFe chemistry is considered safer than LiPo, with a slimmer chance of cell failure and a longer overall cycle life, according to multiple retailers.
Compatibility: Its slim stick design is ideal for fitting in tight spaces such as handguards or stock buffer tubes of rear-wired airsoft replicas. Users are reminded to always check dimensions for compatibility.
Charging: It requires a specific LiFe balance battery charger. Users are strictly warned not to leave it unattended while charging and to use a charging safety bag.
Quality Control: The batteries are produced in an ISO 9000 quality control accredited manufacturing plant.