M4T28 BR12SH1 DIP4 50PCS/LOT|Replacement Parts & Accessories| - AliExpress
M4T28-BR12SH1 M4T32-BR12SH1 ST Microelectronics Real-time clock and TIMEKEEPER® SNAPHAT® battery with crystal Description The M4Txx-BR12SH SNAPHAT® top is a detachable lithium power source for ST's serial real-time clock and non-volatile TIMEKEEPER ...
M4T28-BR12SH1 datasheet - Lithium Battery (48mAh) And Crystal For Timekeeper