Fronius SYMO 25KW Light The three-phase Fronius in power categories 25.0 and 27.0 kW perfectly meets all the requirements of large-scale installations. Thanks to its light weight and Snap inverter mounting system, this transformerless device can be installed quickly and easily either indoors or outdoors. This inverter series sets new standards with its IP 66 protection class. In addition, its integrated all-pole string fuse holders and optional DC fuse mean that string collection boxes are no longer required.