Hard chrome plated steel hoop mandrel,with a threaded rod attachment for handsfree use! 12" hoop mandrel includes hardened steel rod feature. Easily screws on to the bottom of the mandrel and extends just enough to fit in a vise or simply put in a hole in your bench or work table. Holds securely and is easy to use. Mandrel tapers from 3/8" to 2" (10mm to 52mm)