It is designed according to chapter 16.5 relevant standard requirements of clause no, 4.4.4 of IEC. Technical parameters: Power supply: AC220V±10% 50Hz The diameter of the screw thread mandrel Φ12mm Matching with 3pcs screw thread mandrel. The dimension is E14/19mm,E27/25mm (can order the other specifications) Weight: 3pcs, the weight is10N (combined)