Disambiguation: Myke-4 Astor, Adult Legion timeline
First published in: 1967
This version of Echo appeared in: Adventure Comics (DC, 1938 series) #355 (April 1967), Superman / Batman (DC, 2003 series) #17 (March 2005), Superman / Batman (DC, 2003 series) #18 (April 2005)
See also the Echo of the Mainstream Universe.