Original vintage ad for KLH RESEARCH DEVELOPMENT CORPORATION.  Model Nine speaker is tall, handsome, expensive, requires 30 watts or more.  It separates into two elegant sections for stereo.  Only one company can make a full-range electrostatic reproducer which radiates as a dipole over its entire range.
Main office was located in Cambridge, MA.
This unique old one page 1961 high fidelity stereo component equipment trade magazine advertisement would display beautifully matted and framed.  It would make a nice accompaniment to your vintage stereo.