The NAFW507840 is a Light Duty Open Type . Double Row Machined Needle Roller Bearing with an Inner Ring. Both the Inner and Outer Ring are easily separable from the Needle Roller Cage and the Outer Ring has an oil groove and an oil hole. The Needle Roller Cage means that these Bearings have excellent rotational performance and a simple structure with high accuracy and high speed. These Bearings are most suitable for mass-production . high running accuracy applications like Machine Tools . Printing Equipment . and Textile Machinery. The bearing dimensions are 50X78X40MM.