Version 2.0 Posture Correctors: We have re-designed the adjustable straps to give more range of motion and padding to rectify sizing issues some users were having | Different Sizes: e v2.0 Posture Correctors should now cover a much wider range of sizes both for initial use and for tightening as the posture begins to improve. | Comfort: Yes, unfortunately. Until you get used to the feeling, it is completely normal for users to experience some slight initial discomfort. | How it works: posture corrector works through applying a mechanical force to reverse years of muscle memory and promote tissue adaptation | How long will it take?: Again, this is going to depend on each user's individual adaptability as well as their starting situation and diligence in use. Another way to think about it, is how long it takes for bad posture to develop in the first place