Does the head on your T-800 droop forward, i.e cannot support it's own weight?
This clip pushes into the upper neck and reduces the droop. It pushes in from the back. Keeping the head tilted forward, once in, using a screwdriver, push the part round until the large part is at the front. The more it goes to the front, the less the droop.
Note - watch the video clip on how to apply.
This does come in black, although you could paint silver before applying.
You'll receive 2 clips, as we know accidents happen. They are delicate, so care will be needed.