Current EPIRBs are generally divided into three classes; Category I, Category II, and Class B (or Category B).

* Category I EPIRBs are considered the best but are also the most costly. Category I EPIRBs can be either deployed manually or set to deploy automatically in the event of a disaster at sea. These EPIRBs are generally housed in a specially designed bracket on deck and the buoyant beacon is designed to rise to the surface and emit two signals, an emergency homing signal on 121.5 MHz and a digital identification code on 406 MHz that can be used to identify the stricken vessel. Category I EPIRBs used in American waters must be registered with NOAA.

* Category II EPIRBs are similar to Category I EPIRBs but are generally manual deployment only. Also like Category I EPIRBs, Category II units must be registered. Category II EPIRBs are also generally less costly averaging less than US$1,000.

* Class B EPIRBs, also called Category B or "Mini B", operate a 121.5 MHz homing signal only and are usually manual deployment only units. They are the cheapest units but also the least capable. Since the signal has no identification component, Class B EPIRBs are not registered. Due to their limitations, Class B EPIRBs are slowly being phased out. The International Cospas-Sarsat program will no longer monitor Category B EPIRB signals as of February 1, 2009. Although the U.S. Coast Guard no longer recommends them, they remain in wide use.

EPIRB Best Practices
Understanding EPIRBS
EPIRB Terminology