If you are missing the center caps for these wheels they don't make them any longer unfortunately.  However we may have a solution for you.   Check out the Ro Center cap.   

For 6 lug Chevy/GMC (Ford 2015 and after) fitment go to BLACKRO6LUG for black or for chrome go to RO6LUG 

For 6 Lug Ford 2004-2014 go to BLACKRO14x2 for black or for chrome go to CHROMERO14x2

For 6 lug Toyota go to RO61215B for black or for chrome go to RO61215C