1" diameter blank collet without hole or slots. It is made from free machining steel so you can drill and machine it to whatever shape you need. The shaft is pre-machined and threaded to accept your WW collet holder. The 3/4"-16 Arbors provide a way to mount a Sherline 3-jaw or 4-jaw chuck to this type of lathe. The ability to mount these chucks adds a great deal of versatility to this type of special purpose tool.