Review (5/5): These pens are convenient and work well!
I bought this pack to share with my son. He's been using one and I have used the other. It is very convenient to apply the gel quickly and results seem to be fast. We've both noticed whitening within a few days and are happy with the product! For the price, they are well worth it and I wouldn't hesitate to recommend them. Also, no sensitivity which is really nice!