ME22 is a further development of the popular Endless ME20 compound. ME22 has better cooling properties then ME20 and can in some cases lower the overall disc temperatures compared to ME20. ME22 has the same basic properties as ME20 and is suitable on both race cars and street/trackday cars.
ME22 has little bit lower friction level than ME20. And including much graphite for rubricating. So the friction is so stable and not shows high build up tendency in the braking.
For the corresponding rear brake pads for the Alfa Romeo 4C, you will need the Endless Alfa Romeo 4C ME22 Rear Brake Pads.