Real-Time Clock (RTC) is a module to be used with a clock port available on
Amiga 1200 motherboard. It keeps track of the current date and time. 
It uses CR1220 coin-cell battery (NOT INCLUDED).

Compatible with: 
A1200 Clock Port 
A500 Memory Expansion 
A600 Memory Expansion 
A604n Memory Expansion 
ACA1220 128mb Accelerator 
ACA1232 128mb Accelerator 
ACA 1233n 128mb Accelerator 

Turn off your Amiga, plug in the RTC Module (see pics), 
set the time in your Workbench preferences and you are ready to go.

Note:
Some Amiga 1200 motherboards do not have the 22-pins clock port, marked P9B (the pins need to be soldered) or they have them installed in the wrong location.
Be sure to check before installation.