What size of banana plugs should I use? 1 year ago 4mm Banana Plugs are recommended for use when connecting to our Amps / Stereo Receiver's output terminals. Related articles What Size Banana Plugs are compatible? What would the power output of the CXA be if I connect two pairs of speakers? What's the difference between the CXA81 and CXA81 Mk II? A1 User Manual CXA61/81/81 Mk II Manual