{HEAD ~ The case} mainly has a power out socket connected to the battery through the circuit board, {TAIL ~ a power input socket} connected to the battery and a power supply switch connected between the circuit board and the battery 
mainly has
{ HEAD ~ The case } mainly has a power out socket connected to the battery through the circuit board , { TAIL ~ a power input socket } connected to the battery and a power supply switch connected between the circuit board and the battery
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