Rescue-8 friction descent device is a step up from your normal Figure-8.
The wide mouth creates more curvature in the rope as it winds through. This produces less friction which translates to a faster, more exhilarating ride.
Of course that’s not its main purpose, just a side benefit.
Horns on the side provide numerable ways to pass the rope through. Use this to control exactly how much friction you need for the weight you are carrying. Or tie off altogether for suspended activities on the line. Such as rescuing someone! Guess that’s why its called a “Rescue 8”.
And being aluminium it’s very light weight too.