This Eminence APT3 adaptor is for converting the APT50 HF Driver to 1 3/8" 18NEF extension for mounting on the following co-axial speakers:
Beta-8CX, Beta-10CX & Beta-12CX
The Eminence B2S adaptor converts a bolt-on driver to accept a screw-on horn.
2x 1/4-20 or 3x M6 driver to 1 3/8" 18NEF extension horn.