Baradye pistol was a Fremen invention, another testimony to sophistication of Fremen technology, and their ability to make use of whatever materials were at hand.
It was used for measurement or signaling in the desert. Its primary purpose was to mark off a large area for dye which could be used in the capture of sandworms, or to signal spice merchants approaching from the air.
Unlike the maula pistol, this device used a static charge.
It was usually found in a Fremen Fremkit.