An Operational Evaluation Unit is a type of "reserve" squadron of the Royal Air Force. OEU squadrons are tasked with evaluating an aircraft's weapons, systems and performance. This is to either assist in bringing the aircraft to an operational capability, or to continually assess how to best utilize the aircraft's capability once its in service. An example of such a squadron is No. 17 Squadron of the RAF. The Squadron's role as the F-35B Operation Evaluation Unit is being tasked with introducing the JSF aircraft into service with the Royal Air Force. It is equipped with four F35Bs and currently operates from Edwards Air Force Base in the United States.