Features: 1. Charging indication: LCD screen would display the word 'IN' when charging. 2. Output load indication: After connecting the load, long press LED switch to start the output. Then screen would show the word 'OUT' and output voltage/current 5V/1A or 5V/2.1A. 3. Protection function: Integrate lithium battery protection circuit to prevent overcharge, overdischarge and overload. 4. Connect the battery positive pole to B+, connect the battery negative pole to B-. 5. Can connect one lithium battery or multiple lithium batteries in parallel. But the following conditions must be met: capacity20W mAh, 3-4.2V voltage. Specification: Size: 58*27*15mm / 2.28*1.06*0.59in Weight: Approx. 13g Package list: 1 x Dual USB Power Bank Module Note: Please do not reverse the polarity connection of lithium battery, or the battery will burn out! Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Dadangjia