Amazing fit. It really works.
Took me a few tries to get the impressions right. I had to pay an additional 20 bucks to get more putty, but they are very good at looking at your pics and telling you whether to mail in the impressions or try again. first time I rolled the putty so long, it started hardening in my hand before i could put it in the tray. The next 2 tries were rejected by them when they saw the pictures i took. Third times the charm. The impression looked sooo bad, didnt think it would result in a tray that fits. But my god it fits like a glove.
My only complain would be that the permanent retainers I got from invisialign were made of harder plastic while these ones are made of softer plastic that is more like the temporary trays you go through with invisialign. Either way its way cheaper then them to get 2 sets of trays.