This bearing is also known as: 
FAFNIR: 203KRR5 
BCA: 203RRAR8 
IHC: 611928R91 
Tye: 522-20SP
AC: 562134

DIMENSIONS: 
BORE: .515" Round 
O.D. 1.57" Flat 
IR Width: .72" 
OR Width: .472"