There is fewer parts and the drive system is more durable. There are only 3 moving parts in the whole machine. I have done away with the connecting rod and the the wrist pin as well as the screw and bearing. I use a cam follower now and it has the 3 built in strokes like all my machines. The give system is more refined with myself doing all the machining I can get better tolerences than having someone else run my parts and not giving a damn on fit and function. All parts are made by myself except the motors which are the same ones in the Rapier II. This is the Rapier III model.