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. (Door Width times 2) + 2. Door Width? (Half of Track Length) – 1. For 4 Doors, Track length Fit door opening. (Door Width times 4) + 2. Door Width? (A quarter of Track Length) – 1/2.