The above red ring marked is the MOS set from the PCB. One MOS can support and control 3A current.
ACEBEAM flashlight needs at least 10A current from the high drain cells, so ACEBEAM battery built-in 4 MOS in PCB to make sure be released 12A current.
PS: The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET). It has an insulated gate, whose voltage determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals.