The s300 version 3 is a plug in module to the OBD1 factory Honda Engine Computer (not included) which vastly expands the capabilities of the factory ECU. Forced induction, data logging, real time programming, Bluetooth and engine protection are but a few of the comprehensive s300 features. Designed, manufactured and assembled in the USA. There are rectangular frame ECU (US) and square frame ECU (Japan) versions of the s300. The S300 uses SManager software for tuning and datalogging.