Scrolly is sold on Amazon as well as on its own store, and the Amazon reviews are collected on this site in full, each one marked as a verified purchase.
Three things come up again and again. The first is that there is no subscription for the phone - several reviewers name it directly as the reason they chose this over app-based blockers that charge monthly. The second is that the physical step works where software did not: more than one reviewer describes having overridden the screen time limit built into their phone, or deleted apps only to reach the same sites through a browser, and says the tap barrier held where those did not. The third is the keychain, which reviewers treat as the thing that makes it usable away from home.
Reviewers describe specific drops in their own screen time rather than talking about the device in the abstract - one reports going from around five hours a day to under three, another a two-hour drop in the first week. Several mention the focus coins, outfits, streaks and rankings as the part that kept them going past the first few days. These are individual accounts, not a study, and every one of them is linked so you can read it in context.
The most concrete one is about the keychain attachment: a reviewer worried the links might not survive long-term use and suggested a carabiner clip would make the tag easier to move between a bag and a set of keys. Several also note that motivation is still required - the device removes the automatic reach, it does not make the decision for you. And more than one flags that you need both the tag and the app, since the app alone will not block anything.
The Amazon reviews are reproduced on the main page of this site, alongside the video reviews and the buyer feedback from the official store, with a link to each original.