The H&R Threaded Body Coil-Over suspension Systems come directly from engineers who design and develop racing suspensions. Designed from the ground up as coil-overs (not just a modified shock body), the H & R units are hand-made in Germany by H&R Spezialfedern, under ISO9001 Quality Assurance Standards. Strict attention to function of the complete suspension system is the number one design priority. Threaded body means that the outside of the strut or shock tubes are threaded like a bolt. This allows the threaded spring perch to be moved up or down to fine-tune the ride height, optimizing looks and handling.