Tacx

Ball Bearing Shimano 9/10 Derailleur Pulley Set

Purchased because I wanted sealed bearings on both the guide (upper) and tension (lower) pulleys on my Ultegra derailleur. If you have Dura-ace I wouldn't bother because they already have both pulleys with sealed bearings. I would replace Ultegra or 105 with these in a heart beat because Ultegra only has one sealed bearing pulley (tension) and I don't recall either of the 105 pulleys as having sealed bearings. These are great for the money (<$20) and spin as easy as the Dura-ace pulleys (~$50). I have heard that some pulleys can make your shifting worse unless they are the ones made from the derailleur company, but I have not experienced any shifting problems.

Super smooth, gave new life to my older but still proficient lx derailluer. Good buy!