This looks to be the correct bearing
http://www.bocabearings.com/bearing-inventory/Radial-Bearings/20832/0-125x0-375x0
That link doesn't work for me, I get an item not found message.
Not that it really matters for me, but might help others who may eventually have problems with the new ones, mine are the old type like in the link that Dale gave above. Mine looks to be the same size bearings, but without the flange. I didn't take it apart, but I think my bearings are going bad after all. I first noticed sort of a vibration that could actually be heard and felt in the mast it was mounted on. I replaced it with my spare, and tried cleaning it, and it seemed to turn smoothly. But playing with it some more, it seems that if I spin the cups just right, I can feel that vibration, kind of like it's unbalanced, again. But the vibration seems higher rate than the rpm of the cups, so I'm guessing there must be a flat spot on one of the rollers or something.
After almost 13 years of use, I wonder how many millions of revolutions it's made. I guess I could figure it out from the average windspeed. I don't know that it's worth fixing at that age, may just keep it as an emergency spare or for parts if the new one goes bad. And looking at it, and from the descriptions given in that link, I'm not sure if it comes apart as easily, or at all, as your newer one does. It tells what bearing to use, but says the assembly is glued and sealed. Light synthetic oil may help for a temporary fix if my other one goes bad and I get in a pinch.