van aken smart box for 03-06 LLY engines,, easy to install in less than ten minutes,, no cutting or splicing it plugs right in,,3 position switch ,, off ,,90 hp and 150 hp,, adds 3-5 more miles per gallon,, and alot more power and torque up to 800 ft lbs,, on my truck it aded 100-120 more miles per tank,, i bought a new truck thats why im selling it,, i will sell for 350 ,, with the fuel prices it pays for itself fast