Automatic ventilation at adjustable time intervals (4, 8, 12 or 24 hours) if no manual switching on has taken place within the time phase. When activated manually (e.g. via light switch) there is a run-on time of between 0 and 21 minutes, continuously adjustable. For installation in flush-mounted box behind the switch. 230 V, I min. 0.05 A, I max 0.8 A (ind.). ,