hard to apply accurately [SEP] after applications i do not see the effects yet although i feel the sensitivity so it has the peroxid workingmy main complain is the applicator tip the goo comes out in the middle of it and it has some rubber bumpy thingies around the surface of the tip is relatively large and you do not see the edges or the goo why applying it as it faces your teeth so i would say it is much harder to apply this right next to your gum line accurately than some other whitening pens having a pointy bristle topthe idea is good but currently i would prefer a smaller tip even as a tall male stars for now let me use it for a while and update the review if my opinion changes