Genuine Terminator 3 screen used set prop

I have here an actual piece of one of the terminator tanks that rampaged in the office in Terminator 3. I do not know which one it came from, but it was most likely either T1-8 or T1-7. Two set photos are included for reference, as well as a photo of it with a pen, which is not included. Only the little grey terminator piece is included.

In the photos, look at the face, right below the nose. Each tank had two of these pieces. I do not know what it is made of.

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