Hub center (meaning it fits over the vehicle hub and therefore does not put additional pressure on the wheel studs and also improves wheel balance. Spacers provide a fantastic view of my 2001 Toyota Tacoma, at where the tires ride in flush with the fenders giving an overall more powerful look and slightly better handling as my footprint is now 3" wider as each spacer is 1.5". I use them like my Tacoma and 4runner.