Boys versions (size 2 - 18) of our adult shirts are available for $24. A link at the bottom of each adult shirt will indicate if a boys version is available, and if so, in which sizes. Currently we have Orange, White, Light Blue, Maroon, Navy Blue, Natural Manta, White Manta, Light Green, and Pink. SIZING. The even-numbered numerical sizes of the Boys Guayaberas (2-18), do not strictly correspond to age. They are relative indicators. Below are some measurements of Boys shirts to give an idea of how these sizes go: Size 2 16" - Top of collar to hem. 12" - Across from underarm to underarm. 4" - Sleeve opening. Size 4 18" - Top of collar to hem. 13" - Across from underarm to underarm. 5" - Sleeve opening. Size 6 19" - Top of collar to hem. 13.5" - Across from underarm to underarm. 5" - Sleeve opening.