Bekaert ZA four-point wire in a 1,320 feet roll. Barbs are spaced 5" apart. The wire is 15.5 gauge and galvanized for corrosion resistance. We like it because it's lighter weight & has equal strength (and it's much cheaper!) in comparison to more common 12.5 gauge low-carbon wire. Because it's springy & twisty, you'll want to use bricks or rocks to weigh it down across the top of your bag courses as you build.