Plug (T's) into existing OEM harness and routes a 7-way blade socket into truck bed while retaining use of 7-way socket at rear of vehicle. It works very well. Actually, it's the best thing since sliced bread!! I used it in a 2011 Ford F350. It is also supposed to fit 1999-2011 Silverado/Sierra, 2009-2011 Dodge RAM 1500, 2010-2011 Dodge 2500-3500. 1997-2003 Ford F150/F250 Light Duty, 2004-2011 F150, 1999-2011 F250/F350 Super Duty and 1999-2011 F350/F450 Super Duty. I only used it for 3 months then sold truck. I paid $130.00 asking $75.00 I also have the correct hole saw and drill attachment if interested will sell for 25.00. Thanks for looking