This piece is designed to correct the inaccurate part that comes with the Polar Lights 1/350 Enterprise. The locations that were corrected are the ridges on the 3 sides of the housing. The Polar Lights part has these ridges parallel to each other. When the studio model had these ridges tapper towards each other. See photos as they do a better job showing the differences. The part is casted in a dark color to help with light blocking and put under pressure to avoid bubbles. The casting is so fine, you can see the part numbers from the original piece.