Thundermax Performance ECMs with Integral Autotune System for 2001-10 FXST, 200 - One Size Comes completely assembled and ready to install, no wire cutting or splicing required ThunderMax is a complete factory replacement and is NOT a Flash Tuner or in-line signal modifier Utilizes wide band 18mm O2 sensors for real time AFR analysis and correction at all RPM&rsquo;s and load levels operating as a closed loop control system to continuously self-adjust and properly tune the motorcycles air fuel ration for all riding conditions Easy installation: designed to fit in the same location as the factory ECM. To install remove factory ECM and install ThunderMax, plug into existing harness, change the O2 sensors, load the correct base map from TMAX tuner software and enjoy your ride System includes ThunderMax ECM with Autotune Module, 2 wide band Bosch 5 wire O2 sensors with connection harness, TMAX Tuner software and USB communication cable. Quick start easy install and Comprehensive User&rsquo;s Manual