This is an original replacement part manufactured for use with walk-behind lawnmowers. The metal rope guide mounts to the side rail of the handle, and is secured by a handle knob. The rope guide keeps the starter rope on the upper handle for ease of access, and to keep the rope out of the way while operating. The rope guide is sold individually.
OEM stands for Original Equipment Manufacturer. Simply put, this means that the company who made your appliance is also supplying the replacement part for it.