The "Duane Eddy Twang" lesson covers a classic sound from the late 1950s, early 1960s. The sound is twangy and wet. Often utilizing a tremolo effect, heavy reverb, and even slap back delay. A hollow body style guitar with a humbucker or P90 pickup in the bridge really brings the sound home. Also some sort of tremolo system on the guitar is a staple - preferably a bigsby type.