Price is per pair - includes 190mm brake rotors, axle spacers, #35 / 62T rear sprocket and all hardware. Air pressure should be 12 to 15 psi and never more than 20 for these tires.
Black Aluminum wheels with 15mm axle size (reducers included) - 92mm pit bike spacing - swingarm extension required with Razors
Just like all spokes wheels they may have some wobble to them unless you get them trued.