BetterPosture BackTone Posture Trainer - BackTone BioFeedback Posture Trainer, green, small

The Posture Correcting Trainer helps you develop "muscle memory" that improves your posture for walking, sitting and performing everyday tasks. This lightweight harness features a small electronic sensor. When you slouch, the sensor starts to beep or vibrate. When you straighten up, the beeping/vibration stops. Wear it one to three times a day, up to 20 minutes per session. Within weeks, you'll develop healthy posture habits that last a lifetime. Available in three sizes: S (slight frame, waist 20"-34"), M (waist 24"-39") and L (broad shoulders/chest or tall persons, waist up to 52").