ammoon Swan Tremolo Harmonica Mouth Organ Key of D 24 Double Holes with 48 Reeds Free Reed Wind Instrument with Case Cleaning Cloth 24-hole tremolo harmonica, key of D. Exquisite and light-weight design. Cover is made of stainless steel, good durability. Copper reeds and plate, come out with a pretty good sound. Comes with a plastic case and a piece of cloth to keep harmonica safe and clean.