The floating seals (sometimes it will be called face seals) are a kind of combination seal composed of high-hardness cast-iron seal rings and rubber O-rings. This seal, because its metal seal rings slide across each other, has great durability against wear by silt and sand. 

The floating seals are characterized by two identical metal friction rings mounted one on top of the other and centered in their groove by two rubber components that exercise a uniform axial pressure between the seal and the housing. The first metal ring remains static in its housing while the other, in rotation, ensure the sealing by creating friction between the two components in contact.