I have a smartvest and it uses velcro. The velcro is pretty strong and I'm a weakling but I can pull it open. When I first started using it last year, I was getting muscle pains along my sides and back. I was able to reset the thumping (really like that word, Thumper) to a weaker strength and speed. I do the aerobika during the rest periods in my program and 3% saline at the end. The neb cup fits into the aerobika and supposedly one can do all 3 - vest, aerobika and saline - at the same time but my lungs won't let me do it that way. I can watch tv with the vest but I can't read because the words jump around.