The credits are the internal unit of LabsMobile that are acquired in any purchase or recharge. That is, any top-up adds credits to the account balance.
In this way, any sending (to any destination country or any type of message) consumes the corresponding credits according to the calculation described in What is the price of an SMS message?. In other words, it is possible to use credits from the account balance to send SMS messages to any destination country and of any type.
The correspondence between credits and unit cost per SMS to a destination country can be consulted in the section Services and credits by country.