About this 3D model

This is the drive gear that fits *Overhead* brand garage door opener models 456, 556 and 551. My garage door is model 556 and is the only one it has been tested on. [Installation Instructions PDF](http://www.pdf-archive.com/2015/11/18/gear2817/) [Video of it working](http://youtu.be/S6OWmQmCfOQ)