Well I first got the blue one the first…
Well I first got the blue one the first one the weakest one and then I realized I need a stronger one so I got the dark green one and it is more firm but even so when I bite down on at the way is made it is too easy so I flip it on its side and remove the plastic two pieces and I do at least 35 or 40 four times a day..... I like the results that way personally