Shield

A shield is a non-contact steel closure anchored in the bearing's outer ring, forming a narrow gap to the inner ring without touching it. Common suffixes are Z (one side) and 2Z/ZZ (both sides); such bearings are factory grease-filled and normally lubricated for life. With no rubbing lip, shields add virtually no friction: shielded bearings reach the same speeds as open bearings and run cooler than contact-sealed ones. They retain grease and exclude coarse contamination but offer no protection against fine dust, moisture or splash water. Typical applications are electric motors and fans; in dirty or wet environments, contact seals (2RS) are the right choice.