On this level, you can do most of the features but limited to 1 per feature. That means if you are new to MikroTik and you want to try it on a X86 machine for example, you can get that trial mode and you can use it fully for 24 hours. With this level you have all features enabled for only 24 hours and it is for free. For this, I have taken this table from MikroTik help website which shows all different license levels they have and what features are opened in every level:

Why is it important? Because it limits for you the features that you can do on your MikroTik product. Also, this allow you to upgrade your RouterOS forever whenever there is a new RouterOS version, and again, it is free of charge. And this license is a lifetime one, meaning that you do not require to renew your license every year like some other competitor brands of MikroTik do. The good thing about MikroTik product is that when you buy one Router or switch or CPE or whatever MikroTik product you buy, then it comes with a license. This is something you can see when you go to the following:

We have seen from the previous LAB that my router has a license level 4.

Mikrotik x86 license