In an English-speaking country like the United Kingdom, the International English Language Testing System (IELTS) is an exam that aims to test your English. To achieve this, IELTS is comprised of a listening test and a speaking test. 

The most obvious difference between these two parts of the exam is that in the former, you have to do your best to listen to a number of recordings. The latter is much more difficult. You have to imagine that you are in a real exam and make your best effort to speak for a short period of time. 

You can create a customized test by adjusting the settings based on your proficiency level or choosing the topics you want to include in the mock exam.