Default devices in test IO are devices and platforms that are going to be covered in every new crowd test you create in a given product. This way you can save time and set up the device and OS version coverage once for every single test, for example if you are planning to run regression tests with the same scope and device coverage.
In the menu "Default devices" you can pick devices suggested by test IO or create your own set of platform and operational system combinations.
Once you have default devices selected, they will automatically be enabled in every new crowd test you create within this product.
Please keep in mind, that you can always overwrite the default devices when creating a test, in case you'd like to cover a certain model or OS version.