MFJ-557 features a heavy steel base, tone / volume controls

The MFJ-557 Deluxe Code Practice Oscillator features a Morse straight key on a non-skid heavy steel base that stays put on your table. 오실레이터가 부착된 연습 키

The MFJ-557 lets you practice sending code at home, work, riding in your car --practically anywhere -- because it's so easy to take it along wherever you go. A volume control lets you adjust it from barely audible to blaring full sound. You can practice without bothering anyone. A tone control gives you a wide adjustment, from high squeaky'' to low booming'' tones. You even get an earphone jack for private listening. Plug in an external speaker (like MFJ-280) for extra volume in the classroom.

It runs on a 9 volt battery (not included) or 110 VAC with MFJ-1305, that plugs into a jack on the side. When you're finished cleaning up your sloppy fists with the MFJ-557 Deluxe Code Practice Oscillator, hook the straight key to your transmitter and go on the air sounding just like you were born working QSOs.

Don't pass up this super buy. Built-in speaker. Adjustable contacts. Solid. 8½ x 2¼ x 3¾ inches. Black.

Upon our experience with MFJ products, their A/S system is not good and needs too long time for repairing and bad communications. So, you should pay keen attention to decide to buy MFJ products by your judgement and do not blaim to the ham shops.