The three pole busbar is in the L-Design for MCBs of Standard, ABL, Doepke, F&G, Mersen, GE/AEG, Hager, Legrand, Merlin Gerin, Moeller, OEZ, Schneider, Schrack, Siemens, Woehner, Eaton, Noark, Rockwell devices. The corresponding end caps A1 must be ordered separately., eng