The EF 45 ELEMENTS base accommodates the EP1 speaker pole, the EA 600 Power amp module, and the E435 Mid/High unit. The retractable and extendible feet ensure the mounted elements sit on a stable, secure platform. The Speak on/Neutrik/NL4 ports on both sides serve to patch the audio signal in and route it through to further speakers. The NL4 ports on the side panels also let you use a speaker cord to connect Mid/High units mounted on an adjacent pole.