NSFSI Single Nut (Internal Circulation)NDFSI Double Nut (Internal Circulation)NDFSU Double Nut (Internal Circulation)NSFSU Low Noise TypeNSD Left and right stroke ball screwNSFI Single Nut (Flange)NSFE High Lead TypeEngineering Ball SeriesNSFD Miniature TypeNSFI Miniature TypeNRSB Without Flange