DC surge arrester DEHNguard M YPV SCI 1000 3P Type II is not only a reliable protection against surges, but also the safety of the arrester's use are the central point and feature of DEHNguard modular arresters. The product designation alone makes proper selection and application much easier, and the strong emphasis on high safety requirements results in the unit having an additional safety latch. The module snaps into the base and is locked. This protects the module from shocks during transport and from unacceptably high impacts discharged by the arrester. Replacing the module, however, is easy and without tools. Such a convenient effect was achieved by using bolts in the module. In addition, mechanical interlocks are used in each module against insertion of the wrong protective module or insertion in the wrong place.