This product offers efficient protection against transient overvoltages for TNS and TT electrical supply lines in only one device. Low and medium internal co-ordination protection stages are recommended in the Regulation of Low Voltages (REBT ITC23).According to regulations EN 61643- 11 and GUIDE-BT-23 from REBT the type 1 and type 2 are tested and certified. It is suitable for categories I, II, III and IV equipments in accordance with ITC-BT-23 from REBT. The discharge takes place in an encapsulated element which has no external flash. In normal conditions it remains inactive and the normal working of the line remains undisturbed and without any sort of leakage. It can be co-ordinated with other SPDs like ATSHOCK, ATSUB and ATSHIELD series. Common and differential protection is offered for the three lines and also for neutral. Because there is no interruptions in power supply, there are no situations of lost data that may cause inconvenience to the user. The residual voltage is kept low. Through a lightning indicator of failure, a double warning for "no protection" is offered.