Hand Warmer Power Bank Kit Portable Detachable 4-Cell 18650 Power Bank Casing, Batteries Not Included(Blue)

1. Note: The metal strip is the positive terminal, and the spring is the negative terminal. Please insert them correctly; do not reverse the polarity, or the spring will burn out!
2. The kit does not include batteries; it consists only of the main board and the casing.
3. Mold: 4-cell 18650 (Hand Warmer Model)
4. Battery Type: 3.7V 18650 batteries (flat-top, no protection circuit, internal resistance below 50 mohm, 1C discharge rate; each cell’s voltage must be between 3.3-4.2V). Do not use pointed-top batteries; modifications or the use of other non-compliant batteries are not supported!
5. Dual USB Output: 5V/2.4A (MAX)
6. Input: 5V/2.1A
7. Input Ports: Type-C and Micro USB (PD output not supported)
8. Buttons: Long press to turn the hand warmer on or off; single press (green light) for 45 degrees Celsius; single press (red light) to switch to 55 degrees Celsius
9. Battery Level Indicator: 4-level LED battery level display, calculated using the voltage-based method. Please use high-performance, stable-voltage batteries. If the battery is of poor quality, it may cause excessive voltage drop, resulting in the indicator level dropping rapidly and the output remaining at the first or second level. The mainboard automatically shuts down when not in use
10. Features: Includes a hand warmer function. The mainboard is equipped with reverse-polarity protection; if the battery is installed incorrectly, the mainboard will not be damaged. Once reinstalled correctly, the device will function normally. Never connect the positive and negative terminals in reverse. Do not connect damaged or severely degraded batteries in parallel, as this may cause a direct short circuit that could burn out the spring.

Features:
1. Combines a PI constant-temperature heating element with a high-capacity power bank casing, serving both as an emergency power supply and a portable hand warmer for winter use
2. Press and hold the power button to activate hand-warming mode; freely switch between two temperature settings
3. Features dual USB-A output ports and supports charging via both Type-C and Micro-USB input ports
4. Features a screw-fastened design and a built-in parallel battery slot, allowing for easy manual installation and removal of four 18650 lithium-ion batteries (not included), facilitating daily maintenance and battery replacement
5. The casing is equipped with a 4-level LED battery indicator, and the internal battery compartment is clearly labeled with positive and negative terminal connections to reduce the risk of reverse polarity