Efest Slim K1 Battery Charger 18650 20700 21700 PRODUCT HIGHLIGHTS: 1 Bay Compact USB Charger Single charging speed - 1A x 1 LED charging indicator Compatible with 18650, 20700, 21700, 26650 and more Reverse polarity protection protects if cell is entered in the wrong way CONTENTS: Efest Slim K1 Battery Charger USB Cable User Manual ADDITIONAL FEATURES: Fast Charging Mode: 1.0A Auto Detect Charging Function Low Voltage Activation Function Short Circuit Protection Reverse Polarity Protection Over Charging Protection Piano Wire Spring Provides Smooth Sliding Action - 15000+ Tensile Test Chromium Plated Steel Cathode Insures Low Resistance While Achieving A More Precise Charging Voltage SPECIFICATIONS: Input: DC 5V 1A Standby Current: <20mA Activation Current: 50mA - 100mA 1.0A CC Current: 1000mA ± 10% Auto Recharge Voltage: 4.10V ± 0.10V Auto Cutoff Voltage: 4.20V ± 0.05V CV Cutoff Current: <100mA Operation Temperature: 0°C ~ 40°C COMPATIBLE WITH: 3.6V/3.7V Lithium-ion Batteries Most Cylindrical Lithium-ion Batteries Ranging In Size From 10440 To 26650