HKS engineers chose Duralumin as the core material for HKS Cam Gears because its lightweight properties decrease drag on the engine. Precise valve timing can be adjusted and set within the range of ± 20° along a Vernier scale of 2° intervals. Each interval index is laser-etched into the Duralumin and "A" (advance) and "R" (retard) directional markers are also laser-etched on to the cam gear face.