Performance Based Logistics. The "Performance" in PBL is the combined support performance criteria that the war fighter has formally specified. It is typically expressed as Operational Availability. This suggests that the acquisition of logistics is an integral capability instead of piecing together support from among the separate elements or communities of logistics support. This means extending the "integrated" concept beyond the logistics planning stage into the contractual process. Just as a system integrator delivers a weapon or combat system with specified operating capabilities, under PBL the acquisition program would acquire integrated support and sustainment from a single vendor. The advantage to the Fleet is one-stop-shopping. The operator is ultimately interested in availability, not the elements required to make availability possible.