The City Clock is 22 cm (8,5 inches) high and the base is 15cm x 15 cm (6 inches).
It is powered with an USB cable (5 Volts), there is no battery in the clock. You will receive a USB cable, then you will just need to add your local power adaptater (exemple : Iphone "head" charger).
The clock is sold with a 24h program but as it is Arduino based it is possible to hack the code to display what you want.
Typically we will write a tutorial on how to switch the clock to am/pm format.
The circuit as 2 buttons : one to set the minutes, the other one to set the hours.
We have added a module that keeps on calculating the time while unplugged. Then, when you plug it back, you will have the current time and you won't have to set it up again!
Don't see the answer to your question? Ask the project creator directly.