These are standard, cast iron, solid base, pillow blocks.
There are several bearings that can be assembled with these housings: ie:
UC212 series ( set screw) bearings with doubly extended inner ring.
Additionally , HC212 series (locking collar) bearing with double extended inner ring.
THIS SERIES IS LIMITED TO 110MM OD BEARINGS.
The bearing base of these housings is solid, rather than hollowed out at the bolt holes providing better strength characteristics.
THIS IS THE HOUSING ONLY. NO BEARING IS INCLUDED.