Floating Twin Roller Bearing Pillow Block F-TWN-24-OPN-STG for a 1.5" Shaft Diameter, Scrapers, Grease PortFloating Twin (TWN) Roller Pillow Block Bearing for a 1. 5" Diameter Shaft and fortified with 2 scrapers and a top grease lubrication port. Twin pillow blocks cover twice the space on a linear shaft as a single version. This pillow block has two sets of 3 opposing roller bearings mounted on this double sized twin housing, as if two Single Roller Pillow Blocks (SPB) were fused together to make a much larger bearing. This differs from the Double (DPB)