I will review in this talk some examples of RICH detectors operating or being about to, from the point of view of the parameters which determine the Cherenkov angle resolution. The RICH technique is extremely powerful and widely used nowadays in experiments which have to perform particle identification. Depending on the technologies chosen for the detector design, the design resolution can be achieved if important efforts are made, keeping under control the stability of the different components contributing to the Cherenkov angle resolution
