that would be a motor saver. or at least something very similar. i have one of those wannabe motor savers with the mesh screen and the foam inside. works great.
Yes that is a motor saver, I have one on my xxx-nt also. I have the 10mm with the 45 degree stem. They are available in 10mm or 11mm, with a straight stem, 45, and a long 60 for the t-maxx. I use them on all my rides.