Pro-ject Tube Box S vs Tube Box II +Tube Box SE II

Does anyone know exactly where the Tube Box S falls among the other Pro-ject tube preamps? I came across it a few weeks ago, but I can't really find much info on it, besides a pdf of the manual from the company's website. Based off my limited finding, I've gathered that it sells for around $450 USD and allows for cartridge loading, a feature shared by the $700 Tube Box SE II, however its build looks almost identical to that of the $500 Tube Box II. Is the Tube Box S essentially a T.B. II that allows for cartridge loading and costs $50 less? Any info would be great!