Developed at the MACV Recondo School in Vietnam, the STABO Harness was designed to enable the rapid extraction of reconnaissance personnel by helicopter. Named after its inventors, Maj. Robert L. Stevens, Cpt. John. D. H. Knabb and SFC. Clifford L. Roberts, the harness was made from type-13 nylon and formed an X across the back. In order to be extracted the soldier simply snapped the helicopter’s extraction line bridle to the two shoulder mounted D rings. This was a significant improvement on the McGuire Rig, which was essentially a 100-foot mountain rope anchored to the helicopter with a loop at the end for the individual to sit in. Unlike the STABO, riding the McGuire Rig required strength and agility and it was consequently of little use in extracting the wounded.
Equipped with a standard pistol belt, the harness was also designed in part to replace the M1956 / M1967 Load Carrying Suspenders. The STABOs leg straps were folded up and secured by tape or rubber bands against the shoulder straps until needed.
The first production STABO was supplied by the Counter Insurgency Support Office (CISO), which procured 500 harnesses (at a cost of $5 each) for Special Forces in March 1969. After completing safety tests and revising their cost estimates down from $100 to $14.50 per unit, Natick Labs was instructed in May 1970 to procure 1,370 harnesses for use by Army recon units in Vietnam. Both the CISO and Natick models were produced in small, medium and large sizes. However, the Natick STABO had several enhancements, including: padded shoulders, adjustable leg straps and a permanently sewn in pistol belt.11. E308, ENSURE, Records of the U.S. Army Concept Team Activity, Records of the United States Forces in Southeast Asia, 1950-1975, Record Group 472, National Archives at College Park, MD