Practice mute. Unused/unopened, only opened for taking pictures of the contents. I use a mute from the same series for tuba, and I think it might be okay for playing at night in an apartment, depending on the environment. Mute Product Information YAMAHA PM2X Euphonium Pickup Mute Silent brass pickup mute ■ Pickup mute for Euphonium ■ Diameter: 129mm ■ Length: 143mm ■ Weight: 130g ■ Muting level: -25dB～-35dB ■ Accessories: Dedicated connection cable, instruction manual Retail price ¥25,245