How they work is the kit includes a stainless steel ring that is larger than and thus fits over the old seal land. This ring along with a new seal that is designed to fit the ring replace the old inside bearing seal.

Thats really about all there is to it.. Actually there is an O ring that goes between the ring and the inside bearing to seal things at that point as well. Only three small parts per hub, stainless ring, O ring and new seal.