The Ursini stunner is hand-held energy weapon created by the Ursini. It fires a red energy burst capable of stunning an adult human for roughly ten minutes.
The Ursini stunner was used by a Ursini, when Destiny boarded an Ancient Seed ship, that docked with it. On the ship, Dr. Volker discovered that the ship was inhabited by the Ursini, themselves scientists, who were studying the ship. Later, when the Seed ship started to drain energy from Destiny, Dr. Rush tried to stop the action, but was shot by the Ursini blaster, and had to be dragged off the ship.(SGU: "Awakening")
Although the device is never shown onscreen, concept art for it was shown on Joseph Mallozzi's blog.