I don't know what claims are made for the box that your link leads to, but if all you need is an adaptor Purist Audio manufactures one that retails for $75.00.
The other option would be a RCA to XLR digital link such as (again) Purist Venustus, retail at $425.00. Probably less that the adaptor boxes you ask about.
The other option would be a RCA to XLR digital link such as (again) Purist Venustus, retail at $425.00. Probably less that the adaptor boxes you ask about.