CM13 Interference-Resistant Helper Phage is a new, well-characterized mutant of M13KO7 producing on average twice as many virions than M13KO7 with the same level of display. CM13 is well-tolerated by the bacterial host and is compatible all filamentous phage display systems. Our new formulation gives you enough helper to surperinfect up to 1,000 ml of bacterial culture.