Spark Whitening Portable
This company hides the fact that they will auto-enroll you in their 'Sparkling White Club' in their 'terms of service' page. They don't make this clear when you sign up for a trial offer. You will suddenly find that your credit card will be charged (only two weeks after my sign-up and before they mail a monthly refill order) for almost $100 USD. If you don't check your credit card bill, you will lose a lot of money for something you didn't know you signed up for. This practice is morally reprehensible.
They hook you with a trial for only a few bucks, shipping included, then they charge you monthly for refills. I never got any refill but they charged my credit card just the same.
Their web site is: https://www.SparkWhiteningPortable.com
No physical address given on the web site, which should have been a dead give-away.
Reason of review: Poor customer service.