Park Tool FR-5G Cassette Remover with Guide PinPark FR-5G Cassette Remover - Great for Home Mechanics
Awesome tool. Guide slides tightly into a quick release set up but also work on 12mm through axles. It's just as easy to use on either one (The guide doesn't stop it from working on 12mm). Not sure what that previous reviewer was talking about. If you have a splined cassette lock ring, this tool installs/removes them PERFECTLY and IT DOESN'T CARE WHAT TYPE OF AXLE YOU HAVE! I give it five yellow middle fingers!!!!!
The guide pin means this primarily works with quick-release hubs. Consider one without the guide for more versatility.
Makes changing out your cassette a breeze. Should last a lifetime.