Select Stand-Alone Batting Cage Frames are great. They are constructed of 16
gauge steel poles (not 18 gauge which are much weaker) on a trapezoid to
provide maximum stability and protection against the wind. The frame
corner package includes everything you need except for the 10' poles
required for the frame legs and top runners.
You can purchase the 10'
lengths of EMT at Lowe's, Home Depot, or another store that sells EMT.