UCFL201-8E FYH Bearings 2 Bolts Flanged Cast Housing Cylindrical bore (with set screws) 1/2" Inner Diameter Bearing This two-bolt flange has a bolthole center dimension equal to that of the diagonal bolthole center of the four-bolt flange. Therefore, the two different styles are compatible, however, the two-bolt style utilizes less space and also weighs less. Applications is Roller conveyor and environments where mounting area is limited.