Xray X1 wide suspension arms
Coming from Xray and made for the X1 formula car are wide carbon fibre upper and lower suspension arms. The 2.5mm thick parts add 5mm of track width per side for a total of 10mm. Using the parts is especially recommended for high traction conditions and the arms come as separate items usable for both the left and the right hand side of the car.
Source: Xray [teamxray.com]