Service includes new O-rings and complete cleaning and flow testing. You MUST send in whole sets only. No partial sets will be accepted. For instance, if you have a 6 cylinder engine, you must send in 6 ETEC injectors for us to clean and service. The longer an ETEC has sat unused, the lower the chances of us successfully bringing them back from the dead. After 6-9 months, the success rate is near zero.