The Dr. Grip uses an ergonomic grip with a shaft diameter that reduces strain on writing. This high-end model has been upgraded to the traditional Dr. Grip. Equipped with a "flex reflection mechanism" so you can write non-stop without having to replace the lead with a shake. In addition, it is equipped with a "flex lock" mechanism to prevent the lead from coming out due to the flex mechanism during transport. Quiet design reduces the noise of knocking knobs and the movement of the flex mechanism will not interfere with use in silent environments.