The RNAFW506240 is an Open Type . Double Row Machined Needle Roller Bearing. This Bearing has no Inner Ring . meaning the Needle Rollers are mounted directly onto the shaft. As such . the Bearing has better running accuracy as it isn't affected by assembling an Inner Ring with the shaft. The Needle Roller Cage means that these Bearings have excellent rotational performance and a simple structure with high accuracy and high speed. The Cage is separable from the Outer Ring which has an oil groove and an oil hole. These Bearings are most suitable for mass-production . high running accuracy applications like Machine Tools . Printing Equipment . and Textile Machinery. The bearing dimensions are 50x62x40mm.