Pillow block bearings, flange bearing units, bearing blocks, and take-up bearings units all consist of a housing with a bearing mounted in it. They are available in a variety of materials, mounting configurations, and various bearing features. Each mounted unit, including a mounted bearing, acts as a system to position the bearing securely for reliable operation. Read more about each type of pillow block bearing using the links below.While other configurations are available from AST Bearings upon special order, the most common flanged mounted block bearing units are either two-bolt or four-bolt designs. Small two-bolt designs are commonly called flangettes but are of a totally different construction and design to the heavier duty Two-bolt flange series.