That's possibly without the lid? They make it so a standard box with flat lid is too small. So sell an XL lid that takes it high enough to to fit vinyl in. It's possibly stronger as well than a flat lid so it doesn't sag with weight.
It shows the internal depth as 180mm and I've just measured one of my 7" sleeves and it's 182-183mm, so I don't see how they'd fit in this. https://www.ryman.co.uk/really-useful-storage-box-9xl-litre
The power of HUKD lol I'll expire thanks :)
These are the best storage boxes I've ever owned, extrememly sturdy and look great too!