I replaced my Shimano ultegra rotor with this and I saw an amazing performance improvement

Bought them to be the same as I had in my bike, to be used for a second set of wheels. Product is legitimate and with the good quality I'd expect from Shimano. Prompt delivery and good packaging.

great product for a 2nd wheel

Back in 2011, Shimano began to offer their ICE-TECH rotors which they promised would lower temps up to 150 degrees C (302 degrees F), last longer than regular rotors, and possibly get you laid three times a week. While my wife and I have not noticed the three additional times, I have had a pretty good experience with the ICE-TECHs overall, especially the higher-end Freeza models.Instead of the standard steel rotor offered by almost every other company, ICE-TECH sandwiches an aluminum core between two thin layers of steel for the outer ring of the rotor (with the rest of the rotor being made from aluminum). Shimano claims that this will greatly facilitate the passage of heat out to the rotor body, hub, and finned extensions of their disc brake pads. Using an infrared heat gun to measure temps, I found that when comparing the same size rotors (say, 180 mm ICE-TECH versus 180 mm full steel), the temps are indeed lower by about 90 to 180 deg F. So, ... the rotors do work as long as you don't hold unrealistic expectations. According to Shimano, this means the entire rotor lasts significantly longer. IMHO though, these rotors last only about 1.2 to 1.3 times as long as a standard full steel rotor, ... which in turn lasts longer than the typical Kardashian marriage. That may sound good but you also have to factor in that they cost 1.4 times to twice as much as a standard all-steel rotor.An additional benefit of the ICE-TECH rotors, especially the higher-end Freeza models is that a rotor made primarily of aluminum weighs less than an all-steel rotor. For the high-end XTR level SM-RT99 Freeza rotors that I use on my mountain bikes, I have measured a weight of 73 grams for the 140 mm model, 103 grams for the 160 mm model, 129 grams for the 180 mm model, and 173 grams for the 203 mm model (see pic). So yes, these rotors do help to keep your bikes wheels lighter.I weigh 181 lbs and am slightly over six feet and use two 180 mm ICE-TECH rotors on my 24 lb carbon fiber full-suspension race bike and two 203 mm rotors on my 28.3 lb full-suspension trail enduro bike. On both, these rotors (when used with organic pads) typically last me about three years of riding (but my riding is done almost entirely in sunny, warm, and dry California). When the rotors are brand new, they are 1.82 mm thick and Shimano recommends replacement when they reach 1.5 mm in thickness. After my first year of use, I am only at 1.71 mm on my race bike and 1.67 mm on my enduro bike. Overall, I tend to get about two to three years of use out of these higher-end Freeza rotors.When I first began to use these rotors, I also kept a careful eye on their trueness. I suspected that an aluminum rotor would be pretty easy to tweak out of trueness on a rock or root. So far though, I can say these rotors have remained pretty much dead true. It also helps that when they come new, their lateral variance is only 0.15 of a millimeter, ... very precise. To date, I have only tweaked one rotor that I was able to bend back on my truing stand without any problem.Another great feature of these rotors is that they are Centerlock. Instead of using the six-bolt pattern common to all cheaper steel rotors, you simply slide these onto a compatible Centerlock hub and tighten the lockring. Far, far nicer in my opinion and greatly preferred over six-bolt. Centerlock is also better at dissipating heat.These ICE-TECH rotors also just look nicer than the competition. Shimano's design team has done a good job with the 3D modeling of the rotors and their overall appearance. From the photo, you can see a shot of my son's bike which includes the super cool looking SM-RT99 rotor. The only other company that makes rotors that come close in appearance is Hope.Bottom line, ... Are these rotors essential? ... No, but they are fairly nice, although for a relatively high price as well. In my original review, I had qualms over whether these rotors could be used in high heat downhill and enduro type situations by heavier riders. Now, after almost three years using the larger 203 mm rotors on my enduro bike, I can say that these rotors work excellent, even for very steep (greater than 50 deg) trails that are four miles or longer. I would recommend them for all types of riding with the possible exception of true downhill. I can't say how the rotors would perform for a 260 lb rider up in the wet forests of British Columbia racing downhill. All I can say is that these have proven to be excellent rotors, .... five stars.

I ditched the stock rotors in favor of these, and ... WOW!First, they are quiet even when braking hard.Second, make sure you test their 'stopability'. Tested before taking a serious ride at various speeds and conditions. On high-speed emergency stop, I almost launched myself over handlebars.Very happy.