Fashioned from steel, each mandrel tapers from 18 mm to 6 mm and is 12" long with a round, 1" diameter handle. The 3 mandrels in this series are square in profile: item 320-618 has sharp corners, item 320-619 has cut corners, and item 320-582 has rounded corners. Each mandrel is provided with a steel adapter that screws into the handle of the mandrel and allows the user to install the mandrel into a bench vise or into a hole you've created in your work bench. Or, you can install these mandrels into our Mandrel Vise. Either arrangement permits hands-free work. Made in India.