ET+®specialized manufacture the wheel hub rings, it is using the hightest quality AL6061 T6 billet aluminum with hard anodized for durability and corrosion protection.Additional. We also make the plastic hub rings. It is using the top class Polycarbonate. With Quality and durability fuction to perfect fit the wheel. ET+®wheel hub-centric rings feature a ¡®perfect fit¡¯ hub-centric design that makes the rings function as a precise extension of the axle hub, thereby guaranteeing precision wheel fitment. ET+® Hub Rings - for a perfect, beautiful ride!