1 1/2″ diameter cork core with multiple felt layers creating a progressively thicker cover overall. This is always preferable to forcing on too thick of a piece of felt at one time as many stick makers do. It takes more time and more steps to do it this way but the sound is worth it in the end. This is a very warm and round stick and was created by the requests of my current timpani artists. It is essentially a ball stick version of my BCS model stick with a 10-11mm diameter Tonkin shaft. Highly recommended for Shostakovich 1 cadenza and Bartok Concerto for Orchestra for example. Also an excellent lighter weight roll stick. Try this for the solo high F roll in Tchaik 4. *Break in period for this model is approximately 1 week of regular playing for the felt to relax a bit and become even further voiced naturally…or you can voice them more heavily before using if you wish.