The five-lobed shape of the 19th Expeditionary Sustainment Command Shoulder Sleeve Insignia, or unit patch, is an allusion to the Rose of Sharon, the national flower of Republic of Korea where the organization has been serving ever since it was constituted in 1964. The colors red and blue divided by an s-shaped line form a taeguk, similar to a yin-yang symbol and found on the Republic of Korea flag.
That “S” is also a double-reference to the Command, since that is the 19th letter of the Alphabet and it is the first letter in “Sustainment” (or in “Support,” which was the unit designation in 1978 when the insignia was approved). Originally a Support Brigade, the unit has been redesignated several time as Army sustainment and support doctrine has evolved, becoming a Support Command in 1978, a Theater Army Area Command in 1994, a Theater Support Command in 2000, and finally an Expeditionary Support Command in December 2005.