S&amp,S Cycle S&S Cycle 58mm Single Bore EFI Throttle Body/Fuel Rail Kit 106-4408 Designed for riders seeking the greatest possible performance gains from their fuel-injected engines For maximum tunability and performance gains an S&S Variable Fuel-Injection (VFI) module is recommended (sold separately), but any compatible, programmable module with enough capability and tuning range can be used Components must be purchased separately to complete a Single-Bore EFI assembly Made in the USA A S&S intake manifold and either a S&S teardrop air cleaner or a S&S single bore tuned induction kit can be purchased separately to make up a complete induction system