Surge arrester type 3, for 1-phase TNS and TT networks (polarity neutral). Varistor between L and N and a spark gap between N and PE, for installation in a flush-mounted box. Acoustic signal in the event of varistor failure. Cable length L, N and PE 150 mm, dimensions: L=48.5 mm, W=29 mm, H=10.5 mm. Design: with acoustic test plug for checking the buzzer.