Zeal coilover suspension systems use the originally developed X-Coil spring. This height adjustable coilover kit has been designed to capitalize on the very linear characteristics of the X-Coil spring. As such, internal valving has been set to new levels of precision. The Function-Xs has 6 levels of damping adjustment and features independent lower brackets for height adjustment. Due to its architecture, changing the damping setting is simple. The specially plated shock body prevents rust. Aluminum versions keep the units lightweight. All strut type suspension types use a reverse monotube design coilover.