Including spectral analysis of sound frequencies, close-up views of the lathing patterns, and scientific data on the sound produced, you can be sure to learn a whole lot from Percussion Reviews' article on the 20" A Custom Rezo Crash.
To read the full article, written by John E. Johnson, Jr., and more on Zildjian cymals, go here.
To get more info on the Rezo Crash, visit the product page where you can find sound samples, related products, and more.