Set-Screw Shaft Mount—Tighten the screws against the shaft to hold the bearing in place. For high-speed applications, consider clamp-on shaft mounts, which are less likely to slip.

Clamp-On Shaft Mount—The clamp tightens around the shaft for a strong 360° grip. These mounts attach more securely than set screws to reduce vibration. Plus, there aren't any screws pressing into the shaft, so it stays free from damage. Also known as a concentric lock.

Steel and Black-Oxide Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

Shielded—The balls are covered just enough to keep out large particles while allowing air to pass through and dissipate heat.

Sealed—The best choice for dirty environments. A barrier seals out dust so it won't gunk up or wear down the balls. However, these bearings retain the most heat since air can't flow through.

ABEC Rating—Bearings with an ABEC rating meet industry tolerance standards established by the Annular Bearing Engineers Committee (ABEC). They're rated on a scale from 1 to 9. The higher the rating, the tighter the tolerance. Bearings rated ABEC 1 or 3 are precise enough for most applications. If your application consistently runs at high speeds or requires high accuracy, consider bearings rated ABEC 5 or higher, since they generate less friction and heat.