Tilted swivel is for chairs with backs. These chair swivels by Swivlon, are unique in that no steel balls that can rust or fall out are used. The swivel uses high tech polymer rings that have a true 360 degree contact of the two surfaces of the bearing as they turn against each other. There is no steel against steel or nylon against steel movement. The tilted chair swivels have a tilted pitch and a 500 lb rating. The overall measurement is 7" x 7" with a 3 degree pitch.