CPSIA tracking label.

Section 103 of the US Consumer Product Safety Improvement Act requires a permanent mark on children's products, apparel for ages 12 and under included, identifying the manufacturer, the location and date of production, and the batch or run. A one-off print has no obvious batch, which is exactly why POD sellers of kids' apparel miss it. The rule attaches to the product, so it is a labeling and blank-sourcing question before it is a printing one.