Type 2 surge protection device - VAL-MS 600DC/2+V-FM - 2800195
The product photo shows a version for 1000 V DC
Surge arrester for 2-pos. isolated and grounded DC voltage systems 600 V DC, for DIN rail mounting, 3-pos. base element (L+, L-, ground) with remote indication contact, three pluggable temperature-monitored varistors, status message on each connector.