YD2 / YD4 Sway Bar Kit (Stabilizer Set) [Yokomo] Y4-412S It is an optional part for YD-2 or YD-44, stabilizer set. It can be used in both front and rear, and since the stabilizer bar has four types from ? 1.1 mm to ? 1.4 mm, it can be changed according to the setting and driving situation. YD ? 2 can only be used for rear.