This H&R 03-08 BMW Z4 E85 Sway Bar Kit is designed to improve the handling of your BMW Z4. The kit includes a 27mm front sway bar and a 21mm rear sway bar, as well as all necessary mounting hardware and bushings. The larger sway bars help reduce body roll and provide better handling performance. This kit is a great way to upgrade the suspension of your BMW Z4 and improve its overall performance.