The cotton duck ERDL camouflage helmet cover, which replaced the reversible Mitchell pattern version, was procured in limited quantities as early as 1967 but was not standardized until December 1971.1 It saw very little use in Vietnam, though some Marines wore ERDL helmet covers when they returned to protect the U.S Embassy in Saigon in 1975.
1. Military Specification MIL-C-17502C. (30 December 1971)
Support To United States Army In Vietnam - Clothing & Equipment (United States Army Material Command Feb 1967)