UPDATE: Shirts may come in American Apparel 50/50 or Next Level 6210.
AA 50/50 printed with white/blue water base discharge ink on Black for a super soft feel. Discharge ink is somewhat unpredictable in blend shirts (ie, not 100% cotton) so the colors may vary slightly from shirt to shirt.
The blank being used for this shirt is the American Apparel 50/50. You can see the sizing chart here: http://store.americanapparel.net/poly-cotton-short-sleeve-crew-neck_bb401.