Absolutely a must have!
The brake and drivetrain cleaner is like nothing I have ever used! It applies quickly and with a little scrubbing, it really cleans everywhere it is applied. I squirt it directly onto my hydraulic brake calipers, pads and rotors first (as directed) and then go to work on the cassette and derailleurs. It really does wash off as easily and cleanly as the video shows. This stuff is amazing!