Fast information can matter in an emergency: this patch shows the B POS blood type in clearly legible lettering and attaches as a permanent addition to a vest, backpack or cap. At 50 x 25mm it stays compact and leaves enough room next to other markings such as a name tape or rank insignia.
The hook-and-loop back lets the patch be fitted without tools to standard hook-and-loop panels and moved to a different piece of gear whenever needed.