This isone 6004-2RS bearing. Thisbearing willwork with some 20mm BMX bottom brackets and some other applications. It has an OD of 42mm, and ID of 20mm and thickness is 12mm.

This is one bearing; if you need a pair, buy 2!

Be sure to measure yourold bearingtoensure this will fit.The appearance of this part may vary slightlyfrom the photo.