The cooling channels are made accordingly with the parting surface's curve, this keep the even cooling. All the plasic moulding area with optimal cooling The precision cavities and parting surface tooling avoid the chair with sharp edge and burrs Precision air venting design and tooling. Good technician manual polishing plus hard chrome plating keep the chair long time lasting shine. Interchangeable back design inserts. Use 6000x3000x2000 CNC milling machine for tooling. Use 300T pressing machine for cavity & core fixing. Use gun drilling machine for all the holes drilling. QUALITY POINTS: Good stacking Optimal cooling system No flash, no sharp edge Good polishing Strong leg&backrest