Stainless Steel, Ultra Sealed, ABEC 7, Secret Weapon bearings are specially designed for use with electric motor, RC vehicles but can be used in almost any application. The Ultra Seal is a non-contact, frictionless seal that is placed beneath the metal shields so they are still considered maintenance free and lubed for the life of the bearing. These bearings have stainless steel races, balls and retainers. Bearings that are packed in grease will require a short break in period to loosen up. Grease can usually be removed before shipping upon request. Flanged, (.187x.312x.125F)