Like my original review I wish they'd put a better flow control tip on the tube but it doesn't really matter. For the price...glob it on. Unique is the fact it doesn't burn like others. And, for some reason even with the same concentration of ingredient...it is by far the best of the 15+ I have tried.One of my front lower is actually a false tooth put in back in the late 1980's. Broke it in half with a glass playing quarters after taking cold medicine...anyway, dentist put a couple of screws in the base and built the tooth up with a paste of some sort and blue light. Brand new technology back then. Asked him how long it would hold and he said "no idea...1 month or your lifetime"...35+ years and still going.Anyway, as a coffee drinking, chain smoking individual, fighting the stain has been an ongoing process. The other whiteners basically hold it at bay gradually getting darker but still not as white as other teeth between cleanings.My 6 month cleaning is in a month and I can say this product has kept it at about 95% relative to other teeth. All other whiteners about 80%.No brainer. Glob it on.I just finish my treatment with Invisalign. Now that I have the trays wanted to try this. It really work! After 4 days I see a great difference after that I am using it once or twice a week for maintenance. It is not giving me sensibility or discomfort in the gums! Totally recommend!Me encantó este producto fácil de usar, el tono de mis dientes ha mejorado mucho, no he llegado a los 7 días porque lo hago día de por medio para dejar descansar mis encías y que no tenga ningún contratiempo... NO USE LUZ ya que siento que la luz perjudica los dientes.I am a dentist and I approve of this gel! It works great, we saw results the first use. We had an issue with the tube leaking when package arrived, but they shipped us a new tube right away.Company is responsive as original package came damaged and they shipped a new one within a few days after contacting them.Whitening is superior to whitening strips after 1 hour of use. Minimal sensitivity that only appeared after using it 3 days in a row.I've used several other products for teeth whitening and this is by far the best I've used! I've used it for a few days and can already tell a difference! My wife is a dentist and she noticed as well so I shared what I'm using and she was pleasantly surprised:) Easy to use and having a years supply is fantastic for occasional touch up! Highly recommended!This is really great and easy to use at home! A little goes a long way! It's exactly what the dentist would use for a fraction of the cost! My teeth are whiter than they've been in years! Highly recommend!