door component is emitted most strongly at an angle of about 40 degrees above nadir from the bi concave shape the housing component emits light in two directions downward and at a high angle in a lambertian fashion with two maximum light outputs at nadir and 60 degrees the combination of the three distributions is a narrow batwing distribution with a peak intensity at about 40 degrees from nadir fig1 illustrates a top perspective view of a luminaire 10 having a generally rectangular housing 12 luminaire 10 is shown here having a length u201c l u201d of about four feet and a width u201c w u201d of about one foot housing 12 includes a central ballast channel 14 extending along its length u201c l u201d and upper surface ballast channel 14 has a back panel 16 and sides 17 18 wings 20 22 further define the housing 12 and are each a bifold having first and second sections 24 26 respectively as shown for wing 22 and 28 30 for wing 20 shown in fig2 wings 20 and 22 also include attachment sections 31 and 25 respectively as shown in fig3 two end caps only one 32 is shown in fig1 enclose the housing 12 at each end as shown in fig2 ballast channel 14 is closed on its lower surface and within the housing 12 by a bi concave door 40 having two concave sections 42 44 that come together at apex 45.