Flow diverters are making a breakthrough for the endovascular treatment of cerebral aneurysms. Of them, Pipeline is the only device approved in Japan. The first generation device, classic type and advanced one, Flex are compared, and the points of difference are discussed. The tip of a Flex is fixed with two protective sleeves instead of the capture coil in the classic type. This structural change simplifies and facilitates the initial deployment. The pusher wire has been replaced by a larger, elongated hypotube to permit better pushability. Flex is almost completely resheathable due to the introduction of resheath pad. The Pipeline Flex embolization device allows more precise and controlled deployment than the classic type.