Materials: 90% aluminum alloys, 3% POM, 8% of stainless steel (screws, bearings, gears) Process: Own mold, hard surface oxidation, the core components of the high hardness of 100 per cent copper alloy. Performance: worm-type rigging-angle drive, excellent mechanical properties. Unique damping touch. Includes: card cases, main part, standard six fixed-diameter gear rings and two rubber zipper-style gear rings.