Review title is GLO Science Teeth Whitening Pen [SEP] I am not a fan of this GLO Science Teeth Whitening Pen. The clicking mechanism is super annoying- a twisting mechanism would have been so much easier. The thick, bulky, silicone tipped applicator is annoying as well and a lot of the gel gets left in its little bumps and grooves. It doesn't apply smoothly or evenly at all. I have been using it twice per day but have not seen any results. The taste of the gel is absolutely horrible- there's like a weird floral perfume quality to the taste. Do not like.