Be sure to add me to your favorites list Yamaha 1980's Era Electronic Keyboard Replacement 4 3/4" inch 4 Ohm Speaker, Use in Many "PSR" Portatone Models, and maybe Others, Part # XC643A0, Made in Japan! This is a very good condition Yamaha speaker for a full sized key Yamaha keyboard. This is from the late 1980's and was used in several of the PSR models at that time, and may fit others as well. It is 4 3/4" inches in diameter when measured across, 6 inches diagonally with the mounting brackets included. It's 4 ohms, and 3 watts, and is in really great condition and working perfectly. You will have to splice or solder the wires to get them to work with your keyboard obviously. Please make sure your Yamaha keyboard takes this type of speaker with these specs, and it will make a great replacement! The part # listed on the back of it is XC643A0, and it was made in Japan! Please check out my Store!