The second registration, on 5 June 1918, registered those who attained age 21 after 5 June 1917. These men were born between 1896-1897. A supplemental registration was held on 24 August 24 191, for those becoming 21 years old after 5 June 1918. These cards are included in the second registration cards.
The card in this post is one of those rare few that's not for a relative.