Does it's job. Just be smart about application
Used it a few times and it seems to be working ! I can see results! It's messy, of course, it's frigging black powder.  So just pour a small amount into something you can dip . Be smart.  It does whatever isn't your teeth.  Don't go close near  walls or white shirts and such while inuse...the splashes stay pretty good. But overall,  seems to be a cool product and can tell resulst. Which what matters
Rating: 4 stars