Here's what ad said: Genuine, OEM Ryobi Replacement Part Ryobi replacement trimmer head assembly, part number 313318001 Compatible with: P2009, RY15523A, RY15523AVNM
Here's what I got: A head that feels very heavy and looks like it might be long-lasting. But it is NOT OEM and isn't even a very close copy. It requires a much larger threaded bolt than the one on my Ryobi P2009 or my Ryobi 40V 402011 trimmer. Why claim it's OEM when it's not? Back it goes!