This is a booster plug meant to smooth out the running of a Duke 390 around town as they are jumpy. It just plugs into the existing harness. aftermarket part designed to alleviate the leaned down condition of KTM 390 Dukes at lower speeds and smooth out the running Had it on my duke and it made the world of difference imported from germany...costs 250 bucks with shipping,...yours for 100. condition new.(my 390 was traded in with very low milage)