WARNING: This Product Contains Nicotine. Nicotine is an addictive chemical.

Efest SLIM K4 Charger

EFEST Slim K4 Charger

Compatible with Lithium IMR 3.6V/3.7V Batteries: 10440 / 14500 / 16340 / 17340 / 18350 / 18490 / 18500 / 18650 / 26500 / 26650 / 20700 / 21700

Cost effective and easy to use, the Slim K4 charger comes with a user manual and packaging with instructions in 7 different languages. Incredibly lightweight and conveniently portable!


Input Power ———— DC 5V 2A

2*1A CC current ———— 2000mA±10%

1*1A CC current ———— 1000mA±10%

4*0.5A / 3*0.5A CC current ———— 500mA±10%

Auto cut-off voltage ———— 4.20V±0.05V

CV cut-off current ———— <100mA

Standby Current ———— <20mA

Activation Current ———— 50mA~100mA

Auto recharge voltage ———— 4.10±0.10V

Operation Temperature ———— 0°C~40°C

Storage Temperature ———— -40°C±70°C

LED INDICATOR DESCRIPTION – After inserting the battery into the slot correctly, the Slim K4 will start charging the battery automatically within a few seconds. The LED indicator lights will show white while the battery is charging and change to blue once fully charged.

HIGH QUALITY CRAFTSMANSHIP: Spring made by piano wire, it provides a smooth sliding action when installing and removing batteries. Steel cathode with low resistance and hard chromium plating processing to achieve a more precise charging voltage. 15,000 + times spring testing quality warranty.

USB PORT DESIGN – The Type-C USB port reduces the heat of the port effectively.