The Posture Trainer that helps you improves your spinal fitness   
ZEGRA® Posture-Trainer      YouTube

The function of the ZEGRA® Posture Trainer is to assist and motivate you during the acclimatization to an upright and healthy posture. It is strapped to the chest, just like a heart-rate monitor. Whenever you slouch too far, the ZEGRA® Posture Trainers vibration alarm reminds you of a healthy posture.

Feedback Options: The trainer is adjustable, meaning that the user can choose to receive feedback immediately upon a slippage in posture, or after 16 seconds in a slouched pose.
The immediate feedback is recommended in situations when one wishes to learn what an upright posture feels like, or when one is performing heavy lifting, as in that case even a moment of crooked posture could be detrimental. Otherwise, the delayed feedback is a better option, as it allows the user to move outside of a completely upright position without receiving feedback. Thus the delayed feedback option promotes a posture that includes many movements of the spine, which in the long-run is healthier than a rigid and unmoving posture.