The third letter designates the cartridge to be used in the assembly (H for 1-11/16" Outside Diameter of cartridge, E for 2" O.D. cartridge etc.)

The number that follows is the bore size given in increments of a 1/16" (6 for 3/8", 20 for 1 1/4", etc.).

The final letter designation specifies the type of lubrication and method of relubrication (A for oil cup, G for grease fitting, and P for closed with oil, no relubrication.)

Any two or three letter description with four numbers following designates a special or non-catalog item.