--- product_id: 8370037 title: "MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control" brand: "mfj" price: "AED 488" currency: AED in_stock: true url: https://www.desertcart.ae/products/8370037-mfj-enterprises-original-mfj-557-deluxe-morse-code-practice-oscillator store_origin: AE region: United Arab Emirates --- # Earphone jack for private practice Dual power: 9V battery or 110VAC Adjustable volume & tone control MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control **Brand:** mfj **Price:** AED 488 **Availability:** βœ… In Stock ## Summary > πŸ“‘ Master Morse Like a Pro β€” Anywhere, Anytime! ## Quick Answers - **What is this?** MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control by mfj - **How much does it cost?** AED 488 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.ae](https://www.desertcart.ae/products/8370037-mfj-enterprises-original-mfj-557-deluxe-morse-code-practice-oscillator) ## Best For - mfj enthusiasts ## Why This Product - Trusted mfj brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Private or Loud:** Use the earphone jack for discreet practice or plug in an external speaker for classroom-level volume. - β€’ **Stay Put, Send Smooth:** Heavy steel non-skid base keeps your key steady for flawless code sending. - β€’ **Custom Sound Experience:** Fine-tune your tone from squeaky high to booming low with volume control that won’t disturb others. - β€’ **Practice Anywhere, Anytime:** Compact and portable design lets you sharpen your Morse skills at home, work, or on the go. - β€’ **Built to Last with Confidence:** Backed by MFJ’s famous one-year No Matter What warranty for worry-free mastery. ## Overview The MFJ-557 Deluxe Morse Code Practice Oscillator is a portable, heavy-steel based straight key with adjustable volume and tone controls, earphone jack, and dual power options (9V battery or 110VAC). Designed for serious CW enthusiasts, it offers stable, private, or amplified practice sessions backed by a one-year no-questions-asked warranty. ## Description The MFJ-557 Deluxe Morse Code Practice Oscillator features a Morse Code straight key on a non-skid heavy steel base -- it stays put on table and doesnt move around while you're sending! The MFJ-557 lets you practice sending code at home, work, riding in your car -- practically anywhere -- because its so easy to take it wherever you go. Volume control adjusts from barely audible to blaring full sound. You can practice without bothering anyone. Tone control gives you a wide adjustment from high "squeaky" to low "booming" tones. You even get an earphone jack for private listening. You can plug in an external speaker for super high volume in the classroom. When you're finished cleaning up your sloppy fist with the MFJ-557, hook up the straight key to your transmitter and go on-the-air sounding like you were born working QSOs. Don't pass up this super CW buy! The MFJ-557 also has a built-in speaker and adjustable contacts. The MFJ-557 Deluxe Morse Code Practice Oscillator runs on a 9 volt battery (not included) or 110 VAC. It measures 8 1/2 x 2 1/4 x 3 3/4 inches. It comes with MFJs famous one year No Matter What warranty. ## Features - The MFJ-557 Deluxe Morse Code Practice Oscillator runs on a 9 volt battery (not included) or 110 VAC. It measures 8 1/2 x 2 1/4 x 3 3/4 inches. It comes with MFJs famous one year No Matter What warranty. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B00OAHNA10 | | Best Sellers Rank | #511,976 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #81 in Industrial Electrical Oscillators | | Blade Material | Plastic | | Brand Name | MFJ | | Color | Black | | Connector Type | Standard AC Power Plug | | Control Method | Touch | | Controller Type | Button Control | | Customer Reviews | 4.2 4.2 out of 5 stars (377) | | Electric Fan Design | Blower | | Finish Type | Metallic | | Indoor Outdoor Usage | Indoor | | Is Product Cordless | No | | Item Dimensions D x W x H | 3.75"D x 8.5"W x 2.25"H | | Item Weight | 1.3 Pounds | | Manufacturer | MFJ | | Material | Alloy Steel | | Model Name | MFJ-557 | | Model Number | MFJ-557 | | Mounting Type | Floor Mount | | Number of Blades | 3 | | Number of Speeds | 3 | | Part Number | MFJ-557 | | Power Source | DC or Battery | | Room Type | Classroom | | Size | Medium | | Special Features | Portable | | Style | Modern | | UPC | 744288052305 796793893676 702646177954 757183018185 | | Unit Count | 1.0 Count | | Voltage | 9 Volts | ## Product Details - **Brand:** MFJ - **Color:** Black - **Controller Type:** Button Control - **Electric fan design:** Blower - **Mounting Type:** Floor Mount - **Power Source:** DC or Battery - **Product Dimensions:** 3.75"D x 8.5"W x 2.25"H - **Room Type:** Classroom - **Special Feature:** Portable - **Style:** Modern ## Images ![MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Image 1](https://m.media-amazon.com/images/I/71CSErlhoRL.jpg) ![MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Image 2](https://m.media-amazon.com/images/I/71AR8HeZlyL.jpg) ![MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Image 3](https://m.media-amazon.com/images/I/81qnbfVlryL.jpg) ![MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Image 4](https://m.media-amazon.com/images/I/819mwLtjgTL.jpg) ![MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Image 5](https://m.media-amazon.com/images/I/71GbGfy53KL.jpg) ## Questions & Answers **Q: It says practice machine; can it be used in real life applications? If not would you recommend a unit that would?** A: The key can be removed from the practice oscillator base, and hooked up to most CW transceiver / transmitters for real world applications after you are done using it for audible practice . **Q: can you hook paddles up instead of the straight key ?** A: You can not. Paddles need additional intelligence and an additional circuit that will send dots or dashes when you move the paddles right or left. This is essentially like the buzzer on a door...as long as you press it buzzes, when you stop it stops. **Q: Can this transmit** A: Yes, you could transmit with it, but straight keys are so cheap why not just buy another one. **Q: can you wire this to a radio** A: Dear Writer, 10x 4 msg. You can do if your radio has MORSE key wire's input (not morse key speaker input). Simply un-screw two wires which connects to morse key from inbuilt MFJ device then connect radio's morse key wires. Have a g8t day. 73. Mayank Gupta (VU3MFT) ## Frequently Bought Together - MFJ Enterprises Original MFJ-557 Deluxe Morse Code Practice Oscillator Straight Key w/Volume Control - Learn Morse Code - Easy Tutorial Workbook for Beginners: The Easiest Way to Study Morse - LISTEN to Morse Signals with QR Codes! Morse Practice Book for Kids Ages 8+ and Adults - Morse Code Operating for Amateur Radio – Your Guide to Ham Radio’s First Language --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.ae/products/8370037-mfj-enterprises-original-mfj-557-deluxe-morse-code-practice-oscillator](https://www.desertcart.ae/products/8370037-mfj-enterprises-original-mfj-557-deluxe-morse-code-practice-oscillator) --- *Product available on Desertcart United Arab Emirates* *Store origin: AE* *Last updated: 2026-07-14*