The short version
Three different mechanisms and three different daily-use shapes. Apollo for ambient daytime. Sensate for evening wind-down. Hoolest for short intense sessions. They layer rather than substitute.
When is Apollo Neuro the right pick?
If you want vagal modulation that runs in your day — work, sleep, training — without ceremony or electrodes, Apollo is the right shape. The vibrotactile mechanism is indirect but real, the University of Pittsburgh evidence is solid, and 24/7 wearability is the use case.
When is Sensate the right pick?
If a focused evening wind-down ritual with paired soundscapes is the use case, Sensate is the right shape. The infrasonic chest device is the most pleasant in the vagus-modulation category; the trade is sit-down session-based use only.
When is Hoolest VeRelief Prime the right pick?
If you want short, intense parasympathetic priming around training and sleep, Hoolest is the right shape. The dual ear/neck targeting and the founder-published athletic-recovery research are the differentiators. Active engagement required for the session.