Hmmm.
I suppose that it might be possible that the extender shown there can provide a signal so weak that a web page takes 10 minutes to load over that range, thus allowing the manufacturer to claim that it can operate at up to 300m, but I'd think it more likely that the range figures shown have simply been plucked out of thin air and are therefore completely meaningless.
The manufacturer of that repeater is given as 'HOD Electronics' but the only firm of that name that Google knows about is a Dutch firm selling individual electronic components (such as switches, relays, etc) and which appears not to manufacture any type of finished products. So it's impossible to find any independent reviews for it.
A Google Images search though finds the same product sold under various brand names across the world, such as 'Auveach' in Italy, where 26% of Amazon reviewers award it only a 1-star rating:
https://www.amazon.it/Auveach-Ripetitore-Funzionamento-crittografia-One-Click/dp/B07S3F7PC1