Combined arrester with function indicator, for tool-free installation on the 40mm busbar system with prepared voltage tap. The voltage tap (L and N) for RfZ and APZ according to the application rule VDE-AR-N 4100 can be retrofitted at any time using a set (optional). Application: Buildings without external lightning protection and to meet the requirements for overvoltage protection of the electrical system according to DIN0100-443.