As far as features, there are a surprising number of extra capabilities available in the newest satellite locators, including the ability in some units to send text messages. You’ll pay additional subscription and airtime fees for these services, but it can be great to be able to send a message to loved ones letting them know you’re OK. Also keep in mind that your satellite locator, unlike an approved PLB, must be in line of sight with the commercial provider’s satellites for these units to work. All PLBs are designed to be waterproof, but keep in mind that they don’t all float. If you’ll be flying over water, you might want to invest in a marine distress beacon, which will automatically float in an upright position and activate on coming into contact with water. You can also connect a standard PLB to a life vest or raft and transmit an appropriate distress signal, even if the device is under water. Several PLB models float, but be sure to check the specifications before you buy.