This harness allows you to breakout the IAT sensor from the one-piece MAF on GM cartridge style MAF's with the GRAY connector. (If you have a BLACK connector, look to part 108165). By breaking out the air temp sensor, you can move the IAT to obtain more accurate readings - especially in boosted applications. The IAT connector on this harness is the standard GM style that has been used since the mid 80's. You can utilize either a thread in or grommet installed IAT.