These are 15x10, 6 on 5.5, & 3.5" backspacing.Colorado Custom Billet Series - Denver style. Their listing: Colorado Custom - Denver Style Wheel The center caps screw on with the wrench pictured in front of the wheels. The caps hold on the rings that cover the lug nuts as pictured on the 2 outside wheels in the second attached image. They were originally made for a IFS truck. I had the centers machined out to clear the front hubs on 2 wheels as pictured below in the third attached pic. However, I never figured out how to get the rings that cover the lugnuts to stay on without the screw on caps. Then on the other 2 wheels I had the centers machined out just enough the clear the center of the axle shafts, and still leave the threads to allow the center cap to screw on. Pictured below in the fourth attached pic. So 2 wheels will work just like original and still clear the center part of the axle shafts on the rear. I'm selling these because they are not rock friendly with the 33x12.50s I had mounted on them. So, the first time out in the rocks I bent up the inside lip of one of the rims enough that it didn't hold air. I had 5 wheels originally, now I have the 4 I'm selling now. I think they look sweet! They do need a little polishing, but they are not pitted and anything like that. Just hosing them off made a huge difference. $350 (look at the link above, and see how much they were new) Includes 4 wheels, 4 center caps, 4 rings that cover lugnuts, 1 center cap wrench (lugnuts not included) I will ship at buyers expense. I forgot to add that I am willing to trade. Good winch, 4" rear springs, cross over stuff (need all except knuckles), 17x9 steel wheels 6 on 5.5, or any good stuff; just ask.