Shimano Disc Brake Rotor RT66
The RT66 rotor offers excellent performance using the 6-bolt international standard mounting system. The stainless steel braking surface's unique shape and vents keep things cool under extreme conditions and help keep the pads free from dirt and debris.
I have several of these on my bikes: 2 203mm rotors, and 1 180mm rotor. All of them work very well, look cool, don't weigh much, and even under long, hard braking, I've never had issues with these getting overheated and glazing over. I use these with my SLX M666 brakes and have no complaints with their performance and fit. There is one issue. Although 2 came from the factory perfectly straight, the third one, one of my 203 rotors, did not. Normally this isn't an issue as rotors can be easily straightened, but for whatever reason, I have not been able to get that rotor to get true and stay true.