She trades it to Master Roshi in exchange for a submarine. Master Roshi uses the device as a way to spy on Bulma while she is on the toilet, but it fails as he shows up when she had finished. Later, Master Roshi tries to convince Launch several times to take a bath so he can sneak in microscopically and see her naked, but he fails.
Video game appearances
In the bonus level 7-8 in Dragon Ball: Origins 2, after dropping the Micro Band in the toilet, Master Roshi obliges Goku to fight Fortuneteller Baba's five warriors (with Mercenary Tao replacing Grandpa Gohan as the fifth warrior) to find its location through the sea. After Goku won, Baba reveals that the Micro Band is inside an underwater cave and that someone is wearing it, so Roshi asks Goku to go to the Pirate Cave near his island in order to retrieve the Micro Band. Inside the Pirate Cave in the bonus level 3-8, Goku finds that the Micro Band is worn by a Skeleton Pirate. After defeating the skeleton, Goku brings the Micro Band back to Master Roshi, who immediately uses it to try to see Launch in the bathroom, but with no success.