Category I EPIRBs are designed to deploy and activate automatically should your vessel sink and no one has manually released the EPIRB. The release mechanism is activated by water pressure, once the case mounted on the outside of the vessel reaches a specific depth. On inspected vessels, the USCG requires replacing the hydrostatic release mechanism on all Category I EPIRBs every two years. The #9490 works with the following ACR Category I EPIRBs:
GlobalFix iPro (#2846)
GlobalFix Pro(#2842)
SATELLITE 3 406 (#2874)