Answer:
You can read it both ways, I wear; One way it's a number, reversed a snare.
A hole in a pole, though I fill a hole in white. I'm used more by the day, and less by the night.
I scribble forms of the finest letter, And repel elements of the harshest weather. I am an arrow-aimer and a dust-breaker.
It's anything but amusing when this body part gets hit.
Many have heard it, but nobody has ever seen it. It will not speak until spoken to. What is it?
What is always coming but never arrives?