I have tried similar devices in the past (the VoiceAmp). For me it wasn’t worth the unpleasant, distracting noise. You can now experiment with the technology involved (Delayed Auditory Feedback and Frequency Altered Feedback) through free or cheap apps. Metronomes have also been shown to support fluency. If you find metronomes helpful then there are vibrating metronomes available that I think have lots of benefits compared to SpeechEasy etc and are much cheaper. If you find metronomes helpful for your speech you could try the SoundBrenner Pulse wearable metronome.