Usually they are all working days (5 days a week), 8 hours a day, 173 hours a month.
Developers' local time is Moscow Standard Time (MSK), that is:

» 3 hours ahead of Greenwich Mean Time (GMT);
» 8 hours ahead of the U.S. Eastern Standard Time (EST).

Such time difference makes our work for the overseas customers very efficient as long as activity becomes really round-the-clock:

» (1) our programmers work till approximately 7.00 PM MSK (11.00 AM EST);
» (2) then it is turn for our customer to review all the current results, prepare answers to all the questions, test a beta application, etc.;
» (3) so, when programmers return to work their next day (that is the customer's night), they have all the up-to-date info from the customer.

For the customers' convenience our project managers as well as top managers usually are available for on-line communication till 1.00 AM MSK (5.00 PM EST).