A.C.
I've whitened mine simply by flossing & rinsing w/Listerine (generic) at night, & using a whitening pre-brush rinse before I brush my teeth. Listerine makes one but when I realized it was nothing more than Listerine & peroxide I mixed my own up until it tasted like theirs-works just as well. I also use an electric toothbrush & Crest whitening toothpaste.
My teeth would be whiter if I'd quit drinking coffee & iced tea though lol