A pillow block bearing (plummer block) is a mounted bearing used to provide support for a rotating shaft with the mounting surface on a parallel line with the axis of the shaft. Selection of the appropriate bearings can be accomplished based on the shaft size and the radial and thrust load requirements. Pillow block bearings are designed to support a shaft: the mounting surface is on a parallel line with the axis of the shaft. Elongated bolt holes in the base or feet of the unit allow for some adjustment and easy mounting of the pillow block bearing. Certain dimensions and measurements of pillow block bearings are critical to selecting the right pillow block when either the original to the equipment or as a replacement.