Though not essential, sometimes extending the ODBII cable by a couple of feet makes the difference between climbing under your steering wheel and sitting comfortably while performing automotive dianostics. Often times the readers have too short a built-in cable to conveniently plug into the connector under the dash, this product solves that problem.
One note: the ribbon cable comes out of the top of the connectors.On my GMC vehicle that caused a bit of a problem because of the plastic dashboard, which comes down right to the edge of the connector and made plugging and unplugging the cable more difficult. Still, once it is firmly plugged in, it works great!