Parameter: Size: 6.8* 2.3* 0.1cm Allowed 0V change: Yes Dual output current: 5V 1A/2.1A Input voltage B+ to B-: 3.0 - 4.2V Charging cable: Micro USB Input and Dual USB output Button function: Press and hold the button after standby, the LED digital screen displays the power Specification: [LED Indicator Display] The LED digital screen displays the current battery charge while charging. When discharging, the LED digital screen displays the current power, and the display is saved in about 30 seconds (double-click the button to resume display). The system will provide an accurate battery indication after a complete charge and discharge. [Prevent Overcharge Protection] Detection voltage: 4.20±0.05V Release voltage: 4.100±0.05V Detection delay time: <200 ms [Prevent Overdischarge Protection] Detection voltage: 3.0±0.10V Release voltage: 3.10±0.10V Detection delay time: <100 ms [Short Circuit Protection] Short detection delay time: <50μS Release Conditions: Cut off load [Normal Current Consumption] Normal current consumption of PCM: Max 60μA Stanby current consumption: Max 50μA [Suggest Working Conditions] Max continuous charge/discharge current: 1.5/2.4A Suggest working temperature: -5～45℃ Note: The positive pole of the battery is connected to B+ and the negative pole is connected to B-, do not reverse it. If it is reversed, it will burn out!!!! This module is a portable backup power supply with an input that matches the 5.0V adapter to charge the internal battery. Use built-in battery for portable device to provide 5.0V/3.0A USB2.0 supply output for external devices. Package Included: 1 * Dual USB 5V 1A 2.1A 18650 Lithium Battery Protection Power Bank Charging Board