There are many variations of the Rim cylinder, the most marked variation is the number of  pins as with all rim cylinders.

Many manufacturers including Yale, Era, WKS, Century produce standard Rim Cylinders. Yale and Chubb both make very secure variations on the theme for their top of the range Nightlatches which are not directly compatible, however with some modifications they can usually be replaced with a standard Rim Cylinder.

These lock cylinders are normally available in Brass and Satin Silver Finishes.