best teeth whitening machine? Im not talking about White tooth pastes or strips bcz they dont work 4 me?

I want to spectacular successes! Talking about the machines, the gel applied to the teeth

How do ‘Tooth whitening toothbrushes’ work exactly? How do they whiten you’re teeth it’s only a brush?

What do they mean when they say that the tooth whitening product lasts for 12 months?

Does that mean that the teeth back to their original color in 12 months? Or does that mean that the teeth stains accumulated over 12 months and no longer appear empty? Thanks is advance for your reply. I choose the best Anser.

Are all tooth whitening kits as effective? Do they all put the same ingredients in the product?

In the discount store with teeth whitening kits with gel and a dollar tip, and then at the top of shops out there, but for 30 to $ 70 per kit, these are the ingredients the same, right?