This CAT remanufactured fuel injector includes a new nozzle, solenoid, NOP spring, shim, screws, check balls in each injector. All O-rings have been replaced, and injector comes with a 90 day, no-hassle warranty. and has a 12 month, unlimited-mileage warranty. There is an additional core charge of $200. You purchase your fuel injectors from us and pay the core charge up front. We allow you 30 days to send your core injectors back to us. MUST ADD ACE PRODUCT CODE # 9FI639277COR to the order.