Designation:

NA4901 (DIN617, ISO1206, ISO492);
4244901 (GOST 520)

Design:

The bearing consists of two rings (internal and external) and rolling elements (needle cylindrical rollers), connected with a cage.
The name of bearing NA4901 w/o inner ring is RNA4901

Features:

the outer ring with the rollers and cage assembly can be separated from the inner ring