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Reduced Price Deluxe Morse Code Practice Oscillator with Straight Keyer Expand

MFJ Deluxe Morse Code Practice Oscillator with Straight Keyer

MFJ Enterprises, Inc.

MFJ-557 by MFJ Enterprises, Inc.


The MFJ-557 lets you practice sending code easily and anywhere because its so portable.

More details


  • Volume Control adjusts from barely audible to blaring full sound so you you can practice without bothering anyone.
  • Tone Control gives you a wide adjustment from high "squeaky" to low "booming" tones.
  • Privacy: You even get an earphone jack for private listening.
  • Make it louder: You can plug in an external speaker for super high volume in the classroom.
  • Easy: With its straight Morse key and heavy non-skid metal base, learning code is so easy.


  • Volume Control.
  • Tone Control.
  • 3.5mm External Speaker Jack.
  • Encased in a heavy non-skid metal base.

Requires 9V battery (not included). Optional DC power supply can be connected to the power jack on the side.

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