If you notice company logos missing the letters A, B and O, it’s because they’re bringing awareness to a shortage of the blood types A, B, O and AB.

The Red Cross says the blood supply is half of what’s needed, and part of the problem is that just 3% of Americans give blood. Their #MissingTypes campaign is aiming to bring awareness to the problem.

Blood is needed regularly for emergency and scheduled medical procedures and even for basic treatments, like for people with blood disorders such as Sickle Cell.

You don’t even need to know your blood type to donate, the Red Cross says. Donors can bring an ID, do a quick health check, and donate a pint of blood in 10 minutes. Find a donation event close to your neighborhood at redcrossblood.org/missingtypes.html or by calling your local Red Cross office.