As a sandal, it is good as it helps you in deeper dives, and when I say deep, I mean about 15-20 meters approximately, but whoever wants to buy it should take into consideration that it is very hard, resulting in quick fatigue in swimming, which is where I use it, and its shoe is not the softest I have worn on my foot.
Now, as for the positives, I mentioned that it helps for a little deeper diving and it is very durable, it doesn't get damaged at all.
I hope I helped. As for the size, I wear a size 45 in sports shoes and I got it in size 46/47 with a 3.5 sock, and it fits me perfectly

Incredible how durable they are over time.
I have had them for over 10 years and apart from scratches, they haven't suffered anything.
I use them for spearfishing and free diving. They are hard fins, which makes swimming on the surface difficult when I'm spearfishing. However, they are perfect for free diving. I usually wear size 46 in sports shoes, but these fins are size 43. I have them in this size because I wear them without socks, and they fit perfectly.