The Hand Held Emergency Alarm (ZF13) safety sign has a red emergency alarm / horn on the square shaped safety sign.
 
The sign indicates where the hand held emergency / fire alarm can be located and is often used in conjunction with one of the following safety signs:
Location Of Fire Fighting Sign
Location Of Fire Fighting Sign (Diagonal)
The hand held emergency alarm safety sign is also available as a Photoluminescent (glow in the dark) sign as a single safety sign or as a combination of more than one safety sign.
SABS approved safety sign