DOLD 0060939 – MK9143N.38/400 +/-5Hz UH AC230V | JUAL DOLD 0060939 – MK9143N.38/400 +/-5Hz UH AC230V – Mains Frequency Monitor MK 9143N | Relay modules > Monitoring devices > Measuring relays / Monitoring relays > Measuring relays for main monitoring > MK 9143N > Mains Frequency Monitor > Mains Frequency Monitor MK 9143N > MK9143N.38/400 +/-5Hz UH AC230V