Housed bearing - 4 bolts ST491A

How to read the reference of a housed bearing?
Example: 
UCF205-SNR 
Where 
 UC = type and shape of bearing 
F = type and shape of bearing 
205 = housed bearing and bearing dimensions 
SNR = manufacturer's mark 
Example N ° 2: 
FY50-TF-SKF 
Where 
 FY = Type and shape of the bearing 
50 = size identification (diameter of the bore) 
TF = type and shape of the bearing 
SKF = manufacturer's mark