Connecting Leads BLACK 500mm,4mm plugs both end -EIS-PH1055C offers a thoughtfully designed, durable resource for hands-on learning. 500mm length (19.7") 4mm (.15") insulated plug on both ends Great for physics classrooms and labs Black connecting lead. 500mm in length. 4mm insulated plug at both ends. Great for physics labs or any application requiring the assembly of basic circuits.