Pillow blocks are usually referred to the housings which have a bearing fitted into them & thus the user need not purchase the bearings separately. pillow block bearing wholesale are usually mounted in cleaner environments & generally are meant for lesser loads of general industry. These differ from "plummer blocks" which are bearing housings supplied without any bearings & are usually meant for higher load ratings & corrosive industrial environments. However the terms pillow-block & plummer-block are used interchangeably in certain parts of the world.

A pillow block bearing is a type of bearing that is housed within a cast-iron mounting bracket that doubles as the outer housing for the bearing. Typically manufactured from a gray cast iron, the pillow block bearing housing has provisions to allow the housing to be bolted down snugly.

The inner bearing component of the pillow block bearing is commonly a soft metal material, such as white metal, while the outer housing can be a split or single housing. Primarily designed for low-torque, minimal-load situations, this bearing is also designed to be used in clean environments within an industrial setting.