They were Vietnam War's covert special warfare unit. They created the STABO rig which was an emergency extraction rig using special web gear that converts to a harness for attaching to a rope lowered through the treetops from a hovering helicopter. Since then, SEALs and Delta teams have used this method of extraction in dire situations. One of the methods they devised to remain invisible behind enemy lines was wearing boots with asian-sized human barefoot soles. That way, their oversized boot prints could not be detected. They also wore black and even NVA uniforms to confuse the enemy.