A major US operator faced the challenge of connecting a deepwater oil export line to an existing 24"/28" multi-diameter oil export route in the US Gulf of Mexico. There was a strong desire to use a 16" export pipeline to reduce project installation costs. With these extreme conditions, pigging through varying geometries was considered impossible with any commercially available ILI tools. To successfully inspect the line would require a tool to reliably travel through the new 16" pipeline into an existing 24"/28" multi-diameter pipeline. Aside from unprecedented diameter variations, the system includes several challenging top-entry wye geometries. Overall, it was confirmed that a customized inspection tool for this challenging pipeline system was required.