Square extenders

Square extenders are used to link two components together, although you can't attach them to everything, like a wheel. They have four APs

If you use them, well, you're doing it wrong.

One might think there are tougher than round extenders because heavier. Well, NO ! There are heavier and the only good thing about square extenders is that they're easier to work with than round extenders, but if you practice your building skills you will find round ones easier to use.