Incomplete comparison
Incomplete comparison is when you say one thing is better, faster, or more than another without saying what you're comparing it to or on what measure. So the claim sounds strong but is empty. "Better" and "more" are relative—we need to know better than what, and in what way. The fallacy is to use a comparative word without completing the comparison. The remedy is to ask: better than what? In what respect?
Examples
This brand is better.
Our product is faster.
We're number one.
This is the best solution.
We've improved.