Item description on Diode Dynamics site says these will not fit the Pro4X king Cab, My Desert Runner King Cab has the same bumper and stock fog lights as the Pro4X and these fit.I did have to put the mounting bracket on the lights so the light would sit further back, if I placed the light further out, toward the bumper, there would not be room to adjust it.Speaking of adjusting, there is no way, on the Frontier to get to the side screws on the light to adjust the light, once it is attached to the mount. I tightened the screws on the sides fairly tight and the lights can still be moved up or down. Have not tried to aim them yet as it is light out.Wire adapter harnesses looked to be good quality, did not use them as these lights replaced a pair from Rough Country and fortunately, the RC lights use the same plug the DD lights do so I just had to plug the lights in.