What is the difference of resin body and wooden body?
Durable resin body

The merit of the resin body is especially easy to handle. Unlike wood, it does not be deformed due to moisture (e.g.saliva), it is easy to play and airtightness between the body and reedplate is also kept, so that breath leakage can be suppressed. Generally the fewer the breath leakage, with less breath harmonica (reed) response, so that the sound response is well and easy to make music expression. Moreover, due to screw fastening it is easier to disassemble and high maintainability.
Comfortable tones by wooden body

In the tones of harmonica much harmonic tone(*) is included, and this forms a beautiful tone peculiar to harmonica. The more the harmonic tones are included, the brighter and spreading tones are made, but the more harmonic tones in high-tone, the sound may feel uncomfortable. Harmonica made by wooden body will be a comfortable "round and soft" tone as it has the effect of absorbing and suppressing harmonic in high-tone. Resin with natural wood fiber which is adopted for SU-21W also has the same effect as wooden body harmonica. Combined with a newly designed cover for exclusive use, it realizes comfortable "round and soft" tone.
* Harmonic is the other notes that are sounding at the same time when one basic note (e.g.Do,Re,Mi) is sounded. The impression of the sound changes with the content of sounded harmonics, which makes the sound feel beautiful or uncomfortable depending on it's bias and quantity.