Product review (5 stars): This line is great. Way easy to work with and much better ...
The supply line only shown as poly tubing is actually PEX if you look at the description.  This line is great.  Way easy to work with and much better quality than the nylon line it replaced.  I have a difficult hook up for my fridge that a 15 ft copper line was not long enough to reach and the PEX line is so much better than anything else I have used.  Also it is made in the US so it doesn't smell like a Harbor Freight store.