Crossword Clue:

Letters on many ambulances

AnswerCrossword Clue
EMSLetters on many ambulances
POBOXAbbr. on many letters
USSLetters on many ships
AAALetters on many towers
STPLetters on many a racecar
AMELetters on many black churches
OPERLetters under TUV, on many phones
FDNYLetters seen on many baseball caps these days