You can probably make your own using the torus in the "Prop Types". Just resize it, move it to where you want it, then parent it to the head. Change the color, and I suggest that you use the ground texture as a texture for it. If you get what you want, save it to a prop library. A popup will show, asking if you want to save it as a "smart prop". Click yes, and it will be placed in the same place on the head the next time you load it.