I ordered this because a comparable kit I ordered previously was mediocre at best. I used to get the expensive syringes from the dentist but after the closures and being dentist deprived my coffee and red wine drinking began catching up with me causing my teeth to start to yellow, as it seems to want to do naturally unless I keep up on the bleaching. I ordered this one and it took care of what the other one failed to do (get the stubborn yellowing near the gumline). No sensitivity and worked well. Cheaper than the dentist office. My hygienist commented on how much whiter my teeth were. I will be switching to this kind for upkeep.