Product review (5 stars): Worked perfectly
Like all corrugated tubing you want to make sure you have the right size for proper flow even with the bends in it.  This one is rated for 280,000 BTU usage when straight and 25=30% less with bends which was fine for the 180,000 btu unit it was connected to.  All the fittings were well machined and fir right the first time.