Wheels MFG 5/32-inch Loose Ball Bearings
Grade 25 loose ball bearings to fit many brands of hubs, headsets and bottom brackets.
If you have the tools and wherewithal to overhaul your headset or pedals from time to time, these bearings are just the ticket. They're a better choice than caged bearings, because they'll give you more BPI (Balls Per Inch) and therefore spread the load out over a larger surface area. This prolongs the life of the bearings, but since they're dirt cheap, we're more concerned about prolonging the lives of the cups and cones in your pedals and headset, anyways. These bearings will contribute to that as well. If you've never overhauled your pedals or headset and you think it's time, get a copy of the BBB (Big Blue Book) http://www.pricepoint.com/Brand/Park-Tool/Park-Tool-BBB-2-The-Big-Blue-Book-Of-Bike-Repair.axd and set a side an afternoon to put some love on a couple of oft-neglected parts of your bike. Just make sure neither of those parts use cartridge bearings before proceeding. That's a different process altogether.