Thick diaphragm and dual valve structure, powerful and long-lasting power Rare earth strong magnet and brushless motor, efficient, silent and energy-saving Integrated drive and ball bearings for easier maintenance Copper balance wheel for crankshaft, running smoothly with slight vibration From strong magnetic materials and copper balance to professional ball bearings, we insist on using good materials and precision manufacturing processes in the core components, Manufacturer: ZXZZAS