These are showing up on EBAY for sheap...don't waste ur money.
All 121.5 MHz EPIRBs, often referred to as Category B (or “Mini B's) are manual activation units. Although these units do work with the low-earth orbiting satellite system, they do not work as well as 406 MHz beacons, and they can not be detected by the geostationary satellites that provide instantaneous alerting for 85% of the globe. Furthermore, 121.5 MHz beacons are a large source of wasted effort by SAR forces. Most 406 MHz false alerts can be resolved easily with a phone call. In contrast, every 121.5 MHz false alert must be tracked to the source using direction finding equipment. These reasons (and more) have lead the International Cospas-Sarsat Program to phaseout 121.5 MHz satellite alerting on February 1st, 2009. Thus, if you have a 121.5 MHz EPIRB it will no longer work with the Cospas-Sarsat Satellites after that date and you will need to make the switch to a 406 MHz EPIRB!