These high quality wheel spacers are machined from billet aluminium and are available for a wide range of applications. Wheel spacers are used to "space" the wheel out from the hub and are usually installed to give the car a wider track and so the wheels fill the arches better for improved appearance. However, wheel spacers come in two types, flat, and hub centric. Wide flat spacers should be avoided. Yes they are cheaper, but as they are flat, all the load of the car is held by the wheel bolts. Hub centric spacers have a lip in the centre similar to the one on the OEM hub. This lip bears the weight as the original hub would, not the bolts. Hub centric spacers are therefore much safer. Spacers less than 10mm are usually flat, but wider than 10mm, and you should always use hub centric spacers.