Nevermind, I found out.
I found this after a little bit of Googling.
"Vaisala Inc. manufactures the devices under an NCAR license. Each season, hurricanes and cyclones devour more than a thousand dropsondes, which cost $700 to $800 apiece, says Holger. And it’s a one-way trip.
Unlike balloon-borne “driftsonde” instrument packages, which have a return-to-sender label to use if found on land, dropsondes are used for open-ocean work, and sink after service.
But NOAA has no regrets about losing them (more than 30,000 GPS-aided models have been expended since full adoption in 2005), since those models have played a starring role in raising forecast-track accuracy."