IMet-1 RS Radiosonde
This Radiosonde is mostly used in Israel, Belgium, and the USA.
The iMet 4 is a more modern radiosonde, and more compact.
while the iMet 1 is an older model which is almost not used in 2021. It also has a bit wider bandwidth.
402 MHzMegaHertz (MHz) 10^6 Hz — 406 MHzMegaHertz (MHz) 10^6 Hz