The “Connection Type” of styli and extensions can be threaded, conical or cone. 

Conical and Cone are one in the same, they use set screws to hold the styli or adapter in place at a set angle. The benefit of this connection type over the standard threaded connection is the flexibility to adjust the angle of any adapter or star styli. With the multiple set screws holding the connection it is far more secure than a single threaded connection. The video link show the detail of the connection.