The RS4-4 is a medium friction race compound with slightly lower bite and low temperature friction than RS4-2 (Blue), but better wear at high temperatures. Maximum operating temperature is 1050 degrees Fahrenheit. Extremely low disc wear. Very stable torque. Often used as rear pads combined with more aggressive front pads, such as RS-14 or RS29.
This set was briefly mounted on my car for a track day (with new rotors), but after trying a warm up lap twice, we discovered a driveshaft vibration and my track day never resumed. (They were not yet bedded in). I have since sold the car and no longer need these pads. They are in great condition. They were briefly mounted and driven, but no hot laps. Pad thickness is .505”.
These rare pads were used with Brembo calipers and rotors that were made for the rear of Ferrari’s F40.