MLB test lead. From Hirschmann Test & Measurement , this MLB touch-proof test lead features a plug with a sliding insulating sleeve and a pin with a captive spring. Stackable for a tower connection configuration, this 4mm test lead is highly versatile.. Features and Benefits: Voltage rating: 60 Vdc Connecting plug: Ø 4 mm Operating current (max.): 16 A Contact resistance (max): 22 / 40 m PVC flexible cord: 1 mm²