ThunderMax Z309-589 ThunderMax w/AutoTune for Softail 18-20Thundermax; w AutoTune Softail 18 20 Product Details M8 engines Does NOT fit 2021 Models * A 3 Year Limited Warranty covers the Thundermax ECU and the Autotune module against defects in materials or workmanship from the date of purchase by the ORIGINAL consumer for a period of 3 years. * If the product fails under normal use due to an electronic component failure within the warranty period, then the item must be returned direct to Zippers for testing