The Borg–Warner style manual transmission synchronizer has been used for a long time, and the multi-cone synchronizer is also the same basic structure and movement structure as the Borg–Warner style. We developed a new synchronizer called “Lever synchronizer” that inserts a lever between the sleeve, the synchronizer ring (hereafter described as “ring”) and the hub. There are two styles of lever synchronizers, the high performance style and the inverted style. Mass production of the inverted style started in Nov. 1999, and of the high performance style in May 2002. This paper introduces both styles, the detail and the outline of the development.