What are these centers called
 

I have a couple of centers, and while their purpose is obvious to me,
I am not sure what are they called.

http://igor.chudov.com/misc/ebay/tmp/tmp-8769.jpg.html
http://igor.chudov.com/misc/ebay/tmp/tmp-8824.jpg.html

What are these centers called
 

Ignoramus1471 wrote:

I have a couple of centers, and while their purpose is obvious to me,
I am not sure what are they called.

http://igor.chudov.com/misc/ebay/tmp/tmp-8769.jpg.html
http://igor.chudov.com/misc/ebay/tmp/tmp-8824.jpg.html

Miller Lite. ;-D

Hope This Helps!
Rich