The contract is for 17 units of a specific NSN part with delivery FOB origin. This is a sole-source procurement under FAR 6.302-1 for a flight-critical item requiring Government source approval prior to award. Only previously approved sources have been solicited, as they retain essential technical data and manufacturing knowledge not economically available to the Government. Alternate sources must qualify through the design control activity's procedures, but award cannot be delayed pending approval of a new source. Non-approved sources must submit all required source approval data with their offer, or it will not be considered.