Your answer can only be as good as your question, so I'll assume you have a Buell XB 2003-2009 and you live in the United States...
6005-2RS front and 6006-2RS rear is a size denotation part number, pick whatever brand you prefer.
Or go OE if it makes you feel warm and fuzzy: (SPHD sells the All-Balls brand too)
https://sphdonline.com/products/e000...334f6cb0&_ss=r
I have had NO issues with the All Balls brand, but I do install them properly, leaving the hammer in the toolbox. Unless I'm in Montana
I have found repeated bearing failure is usually not brand preference but instead commonly caused by hamfisted people overtorquing the axles. Do That
even once and you squish the center spacer out of dimension and side-load the ball-bearings. They hate that, and it makes failure imminent.
For $12 isn't it worth the peace of mind?
https://sphdonline.com/products/g032...334f6cb0&_ss=r