Inner rings
The inner rings are component parts of the needle bearings, but can also be delivered separately. They are used when the shaft cannot be properly machined  so that it can be the running path of a needle cage, needle bushes, a combined bearing or a needle bearing when the running path must be wider than the standard one. They can also be used as seating surfaces for seals because the outer surface of the rings is hardened and polished.

 Series :IR; LR

It is used either to complete the bearings without inner ring or as a support for oil seals