Click to enlarge

Koyo NA Needle Roller Bearing / Inner Ring

Metric Series Needle Roller Bearing with inner rings.
When the shaft can not be used as the inner raceway, needle roller bearings with inner rings provide advantages. 

When it is practical to finish the shaft to meet the desired raceway design requirements, an inner ring may be used.
Standard needle roller bearings are available with inner rings (such as this NA series) to form a complete bearing. Bearings furnished with inner rings meet the quality requirements in accordance with ISO standards.

Needle roller bearings are available in different styles with and without inner rings and seals.