The ProTran1 ProLight-1000  - Reliable and Redundant 50-1000VDC Max LED Safety Light with 1500VDC surge suppressor, indicates the presence of dangerous DC Voltage on a Light rail, Subway and Third rail line.  Simply connect the light directly to the DC line and the unit is functional alerting personnel of dangerous DC Voltage. Several options available such as flashing, alarms, digital meter, and various LED colors