There is no USAF Delta Force, it was a manufacturers error.
Parker USAF Delta Force
The 1st Special Forces Operational Detachment-Delta (1st SFOD-D), commonly referred to as Delta Force, Combat Applications Group (CAG), "The Unit", Army Compartmented Element (ACE), or within JSOC as Task Force Green, is an elite special mission unit of the United States Army, under operational control of the Joint Special Operations Command. The unit is tasked with specialized missions primarily involving hostage rescue and counter-terrorism, as well as direct action and special reconnaissance against high-value targets
The Parker Vietnam Boot knife Sets according to a Bulletin put out by “Cutlery World” Not part of the U.S. Air Force that is etched on each of the knife blades & only 600 sets were manufactured making each set Very Collectible. The OAL of each knife is 11-1/4", each knife blade is double edged and is 6” in length, one blade is etched “U.S. AIR FORCE 101ST AIRBOURNE”, the second blade is etched “U.S. AIR FORCE DELTA FORCE” and the third blade is etched “U.S. AIR FORCE SCREAMING EAGLES”, the tang on each knife is etches with the “PARKER CUT. CO. SURGICAL STEEL & JAPAN” Logo & all are engraved with the same serial #. This knife is numbered 345
I bought this knife loose, not part of the set and in mint condition. I than had a custom leather sheath made to fit it. There is not another like it.