This RTC ("real time clock") module can be used on a plain A1200, the ACA12xx accelerators (any speed grade), and on the A512/A604n memory expansions. The ACA500plus can also carry one of these modules. It is software compatible with the setclock command (up to OS1.3) and with the workbench preferences of OS2.0 and higher: You can store the current time and date in the module and thus ensure that file generation/access dates are always correct on your harddrive.
The package contains the RTC module and an instruction sheet. The CR1220 battery is not included.
Pictures may vary: Starting 2018, the colour of the board is black.