Sub Dials on an A21J?

[gt rider]

I know this question will be quickly answered but I have not been able to find a straight answer.

What do the subdials and push buttons do on an A21J movement watch? Such as the «economy» ones from Silix. They claim that the subdials are functionnal but I know the chronograph is not..

Ex: http://www.silix-prime.co/index.php?main_page=product_info&cPath=116_234&products_id=2458

[jmb]

Most of them display calendar functions...