NOTE: Door and Install Tools are not included in package. J Shape Roller Bifold Sliding Barn Door Hardware Kit T Shape Top Mount Roller Bifold Sliding Barn Door Hardware Kit For 2 Doors, Track length Fit door opening Track Length ≥ (Door Width times 2) + 2" Door Width ≤ (Half of Track Length) - 1" For 4 Doors, Track length Fit door opening Track Length ≥ (Door Width times 4) + 2" Door Width ≤ (A quarter of Track Length) - 1/2" for 2 doors for 4 doors