I love the simplicity of use packed into a high tech delivery that is compatible with a multitude of power sources even as convenient as using your cell phone to power it! (I use my cell power bank) The solution to prep your teeth is near tasteless and is easy to apply. I am so glad to have invested in the SNOW tooth whitening device. In two 15 minute treatments I was able to see the difference by about two shades. Those first two were the greatest noticeable changes. Now its still getting whiter but not as drastically noticeable. I love the product! Thank you!