3M Speedglas 9100xx Auto Darkening Welding Lens. You can use this lens for grinding all you have to do is turn the "SENS" (arc sensitivity) down to the first setting so it won't trigger the auto dark when sparks are flying. Just make sure you turn it back to setting 2 or enjoy a nice bright reminder (yeah I've done it too). I have this same lens in my work hood and I grind, MIG, TIG, and stick weld in it.
Also works for carbon arc gouging. It is new I just have the lens and sleeve for it no box.