Yokomo RD2.0/SD2.0 Aluminum Rear H Arm (Weight Spec/Short) - Y2-008RAWThis optional part for the RD2. 0 SD2. 0 combines an aluminium rear H arm with a brass weight to systematically increase rear traction. By mounting the weight on the rigid aluminium H arm, the unsprung weight, which is directly loaded on the rear tires, is increased, effectively increasing tire traction. Unlike increasing the chassis weight, the weight is applied regardless of the pitching motion, so the slide is well controlled even when entering a