help identifying a prodct

[WindowMaker]

Hey all, just wondering if anyone can tell me what the fitting used here is called. I am looking at the black fitting that the bracket is attached to. It appears to slip and tighten over the clear pipe and have a nut on the bottom that a bracket could be attached to.

I figure it is a common part as I have seen them used in several places.

thanks in advance for help

http://cgi.ebay.ca/ws/eBayISAPI.dll?...ht_2229wt_1144