These high quality "spice" grinders are machined from 6061 aluminum right here in California at RPM Headquarters. We then sent them out to a local anodize vendor for color. Grinders are roughly 2" in diameter and 1" tall. The fit between both the top and bottom half is a very precise, air tight fit. There are 6 unique colors to choose from and are in a very limited supply. Black, blue, green, orange, red, and clear anodize options are all available.