Pro Formula Whitening Gel Pen – 1,9 ml – 2 stk.

The two-pen pack is perfect for keeping one in my bag and one at my desk, so I never skip a touch-up. The gel applies cleanly with the pen tip and doesn't leave that sticky feeling I've had with other brands—my teeth look noticeably brighter after just a week.

I was skeptical about pens, but the gel applicator makes it stupid easy to hit every tooth without the mess of trays. Two pens in the pack means I keep one in my work bag and one by the bathroom sink.