The GKTECH axle spacers are CNC machined from billet aluminum and are concentric in design to ensure the perfect fit. Our V2 version goes between the driveshafts and the hubs and eliminates the need for longer bolts which under high loads can strip out. We now have the option of a spacer as thin as 0.19" (5mm) which is perfect for lowered cars however when running extended LCA's, S14/S15 subframe in an S13 or running bolt on dual caliper brake kits the 0.39" - 0.59" (10mm-15mm) are more suitable. Without axle spacers the hub is moved out and as such the CV's become more and more prone to damage. These axle spacers resolve this issue. Sold as a pair only. NOTE: We can only confirm fitment on OEM wheel bearings. NOTE#2: Running 0.39" (10mm) or larger spacers will require you to modify the OEM axle nut in order to use the split pin. Alternatively you can run a suitable thread locking compound. NOTE#3: The further that you space the hub out from the drive shaft the less spline engagement that you have. For most cars this will not be an issue but if you're running high levels of torque and/or you have had issues with stripping splines in the past then please keep this in mind.NOTE#4: Z32 300ZX knuckle may need slight shaving upon fitment.