Set of two Used for fork bearings or wheel bearings Pre-lubricated Shielded from dirt Baja Motorsports calls this their steering stem bearing for the Baja Doodle Bug mini bike, although it may be referred to as a fork bearing or head tube bearing This set of two 6900ZZ shielded ball bearings are made of carbon steel, and can rotate up to 48,000 rpm Baja Motorsports calls this their steering stem bearing for the Baja Doodle Bug mini bike, although it may be referred to as a fork bearing or head tube bearing. This set of two 6900ZZ shielded ball bearings are made of carbon steel, and can rotate up to 48,000 rpm. This size bearing is also sometimes referred to as simply a 6900Z bearing. As well as their role as stem or fork bearings, this size is commonly used as wheel bearings. Bearings are closed with metal shields to protect the bearing from dust or any possible contamination and are self lubricated (bearings are already greased). Note that this item is a complet