Combined arrester with function indicator for tool-free installation on the 40 mm busbar system with prepared voltage tap. The voltage tap (L and N) for RfZ and APZ in accordance with the VDE-AR-N 4100 application rule can be retrofitted at any time using a set (optional). Application: Buildings without external lightning protection and to fulfil the requirements for overvoltage protection of the electrical system in accordance with DIN VDE 0100-443.