You must be proficient with wind instruments to use these pipes. While you are attuned to the pipes, ordinary rats and giant rats are indifferent toward you and will not attack you unless you threaten or harm them. The pipes have 3 charges. If you play the pipes as an action, you can use a bonus action to expend 1 to 3 charges, calling forth one swarm of rats per charge, provided that enough rats are within half a mile to be called in this way.