The Vibrajet was based on the H74 Neo-Cutaway, but as the name implies, had inbuilt vibrato / tremolo. As described in the 1965 Harmony catalog:
Built into this handsome Neo-cutaway Double Pickup Electric is a skilfully engineered transistorised and miniaturised assembly (made in America) which, at your command, produces a Tremolo effect through any amplifier. A lever, in easy reach as you play activates Tremolo effect. You control speed of the beat, and depth or modulation,
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