end to prevent coolant from flowing anywhere but through the coolant ports 142 144 fig1 shows the coolant passages 148 with the plugs 150 removed the coolant passages 148 may contain fin features 152 that increase the rate of heat transfer into the coolant fig1 is an isometric view of a distribution manifold 128 fig1 shows the stand offs 136 that are used to mount the housing 120 to the cooling assembly 138 fig1 shows coolant ports 154 156 that supply the manifold the distribution manifold contains to two passages 158 160 that can act as either the supply or return for the water cooled heat sinks these passages 158 160 run the length of the distribution manifold 128 and are plugged 162 at each end fig1 shows a top view of the distribution manifold 128 fig1 shows a bottom view of the distribution manifold 128 fig1 shows coolant ports 164 166 that mate with the corresponding coolant ports 142 144 in the water cooled heat sinks 116 fig1 also shows o rings 168 that seal the connection between the coolant ports 142 144 and the coolant ports 164 166 the n u00d7 m array can be constructed such that the pitch in one direction is the same as the pitch in the other or the two pitches can be different where the pitch is the spacing between leds in the array the array.