Can you help me out with this?

[bwhitworth]

I recently purchased this 2006 X5. So far, I am loving it.

The driver side windshield wiper had some tape around it. When I took it off I found this. Looks like this little plastic piece on the arm may be broken. Can you tell me what it's called and can I buy just this plastic piece? Is it safe to run the wipers with it broken? I doesn't look like it could come in contact with the windshield and scratch it or anything.