Nothing sexy here just clean smooth smooth bearings. 1/4" steel bearings are standard on the rear hubs of many bikes. 50 was more than I needed for one wheel (18 per wheel), but it was so easy I'm now considering upgrading my other bike. While I'm at work 50 doesn't seem like such a big number to me anymore!Tip: Fixing a bike? Find a pair of tweezers with curved tips.This makes it easier to place the tip in the hub and place the bearings along the rail.I also have a set seen with silicone tips from Revain (photo) It would be very useful!