There are basically three kind of LEGO brick separators. All three very easy to differentiate from one of each other.

First we have the Green one, which is th newest version. These ones will work for your LEGO Technic too. And this little tool is a must for all LEGO fans.

Lego Brick Separator Green

Then we have the gray one. This is the most common piece, and works great too. Fortunatelly for those nostalgia LEGO fans, it is still being sold. But since 2011 it is not included in most LEGO boxes.

Lego Brick Separator Gray

And finally, the orange separator, It most definitely works with the tiny legos. The little prong on the top help separate the connecter rods from their couplings. we love this tool. Your dentist will love that your kids aren’t trying to dismantle things with their teeth anymore!

Also, this one is the percieved as most official.

Lego Brick Separator Orange

All three options are excellent options! And are a great investment for less than $10 any of the options.