PKM-BL is a screw-on pen mandrel pre-threaded to 1" x 8tpi. 7mm mandrel shaft (.244" OD). Also includes (7) 7mm bushings, (1) knurled nut, (1) 7mm Brad Point drill bit. Replacement shafts (XPKM-ELC2) are available from Penn State Industries. PSI Woodworking Mandrel Savers (PKMSTS1 & PKMSTS2) are compatible with this shaft. PSI Woodworking has many other mandrels available to meet your specific turning needs: PKMS2SET, PKMS1SET, PKM-ELC, PKM-FLC, PKM-FSM, PKMSMAN1, PKMSMAN2, PKM-AL, PKM-CL, PKMBCM1, PKMBCM2, PKMBCM3.