1. Shortwave Radio Morse Code CW Telegraphy2. Shortwave Radio K4 Heavy-Duty Key, CW Link3. This Is The Teaching Key, And It'S A Normal Key.4. After Opening The Bottom Cover And Installing The Batteries, Turn On The Switch On The Side.5. The Operation Of The Key Will Make A Sound With A Buzzer, Can Be Used As A Common Teaching Key.Production Process: Electroplating And PolishingInterface: 3.5 Audio HeaderUse: Electric Key; Receive SignalColour:silverMaterial:steel+sterling silverSize: 122 x 67 x 57mmPackage Contents:1 x Electric Key1 x Connection CableOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.