This is a practical set that removes mandrel damage or non-circular pen blanks by applying pressure directly to the pen bushings instead of mandrels The mandrel of the pen slides through the center hole of the live center nose, making installation adjustments quick and extremely safe Includes 7mm drill bit, mandrel, and live mandrel saver. The Live Mandrel Saver allows you to attach your pen mandrel to the centerboard without overtightening or overtightening Shaft is made from hardened stainless steel for durability and smooth If you have any questions about the product, please feel free to contact us via email.