Plain and simple: let people know what your blood type is in case of emergency. This is for the people who survive on coffee. It’s for the people who would stick an IV bag of coffee right into their veins if it was a thing. Hardcore coffee drinkers.
Printed neck tag on the inside. No itchiness, no annoyances.
Grenade logo on the back.
Tri-blend shirt is lightweight, breathable, soft, and durable.