they change the wheel bolt pattern. I've seen ones that go from a five lug to a four.... six lug to a five.... pretty much whatever combination you want.

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08 KK OEM skid plates, JK winch bumper w/ Hella 500s, K&N filter, JKS front discos, black out headlights w/ fogs added, blacked out & euro mod tail lights, Curt Hitch w/ oem wiring, OME Springs, JBA UCA & top plates, Cabin Filter Retro Fit, Custom Fender Mounted Light Mounts w/ Hella 500s, ATH roof bars, rear flush mount LEDs