Product review (4 stars): Rinnai 224051 Vent Pipe Extension, 10-Inch
Pricing and shipping:

Amazon.com sells this pipe for about $20 more than anybody else, however they are the only seller offering quicker shipping speeds.  I ordered this from amazon because I needed it next day, and in that respect it was great.  If I was in no hurry, I would have ordered it from somewhere else.  for the price amazon sells it for, it loses 1 star.

Product:

This pipe is what it is.  For my water heater, this is the pipe I need to use, and therefore I got it.  It works good, and gets the job done.