For years glass blowers have known that the easiest way to create a sphere is with a ring. This graphite ring has a calculated inside angle to easily push the glass into a sphere. The angle also provides a different diameter on each side (allowing you to work with different sizes (1 ¾ , 2 inches). By applying shallow heat and light pressure you can finish the sphere without leaving chill marks. Laser engraved ¾ inch walnut handle. Recommended for soft glass only.