T-Harness cables enable you to tap off power and speaker wiring from the car specific radio harness without damaging it. The functionality of the OEM HU will not be affected or damaged in any way.
This gives you the ability to retrofit components such as hands-free equipment, power amplifiers or high-low converters without harming the original radio wiring.
For vehicles with OEM active sound systems the T-Harness only works with limitations or not at all.
Toyota Landcruiser 120 2002 - 2007