User's Manual

8
4.3 Manual G4 in enclosure
Customers who need to mount their G4 in an exposed position can select the
protective enclosure without an HRU fitted (G4c). This means that the G4 will
not
float
free if your vessel sinks. This is known as a category 2 EPIRB. You can tell which
enclosure you have by reading the category from the front of the enclosure:
G4a
Category 1 HRU fitted Automatic float-free
G4c
Category 2 No HRU fitted Will not float free