Epirb

Emergency position indicating radiobeacons (EPIRBs), devices which cost from $200 to about $1500, are designed to save your life if you get into trouble by alerting rescue authorities and indicating your location. EPIRB types are described below:

Type	Frequencies (MHz)	Description
Class A	121.5000 / 243.0000	Float-free, automatically-activating, detectable by aircraft and satellite. Coverage is limited. An alert from this device to a rescue coordination center may be delayed 4 - 6 or more hours. No longer recommended.
Class B	121.5000 / 243.0000	Manually activated version of Class A. No longer recommended.
Class C	VHF ch 15/16	Manually activated, operates on maritime channels only. Not detectable by satellite. These devices have been phased out by the FCC and are no longer recognized.
Class S	121.5000 / 243.0000	Similar to Class B, except it floats, or is an integral part of a survival craft. No longer recommended.
Category I	406.0000 / 121.5000	Float-free, automatically activated EPIRB. Detectable by satellite anywhere in the world. Recognized by GMDSS.
Category II	406.0000 / 121.5000	Similar to Category I, except is manually activated. Some models are also water activated.
Inmarsat E	1646.0000	Float-free, automatically activated EPIRB. Detectable by Inmarsat geostationary satellite. Recognized by GMDSS. Currently not sold in the U.S.; however, the Federal Communications Commission is considering recognizing these devices. This service will end