Arc Euro list some NSK ballscrews on their website with some basic data.
formatting link
The NSK part numbers they quote such as VSP1505N1D0900PP don't seem to appear on NSK's website nor is there anything like them in any printed catalogues. The ballnuts also look significantly different dimensionally to those that NSK list.
Does anyone know if these are a unique arc euro only part produced for them by NSK or what?