This Power Bank Has spring type System. Means no need of soldering any more. Just press the spring and fit your battery. Power bank ready to charge your phone. You can use 4 18650 battery cell maximum. You can connect one battery also. Battery should be 18650 Lithium Ion model. Circuit has Double USB type with 2A charging Current and USB B type charging Socket.
Purchase link - https://www.myinnovation.in/product-page/dual-usb-power-bank-spring-case-kit-4x-18650-battery-charger-diy-box-for-phones
Material: Plastic Spring
Support Battery: 4 x 18650 Batteries (Batteries Not Included)
Input Interface: Micro USB
Output Interface: Dual USB Ports
Input: 5V 1A
Output: 5V 2A, 5V 1A
Capacitor: 20000 mAh max
Four Grid LED Power Indicator: 25%, 50%, 75%, 100%
Product Type: Power Bank Case
Compact size and lightweight, easy for carry.
Easy for operation and convenient for use.
Compatible with 4pcs 18650 lithium ion rechargeable batteries(batteries not included).