Type & Key: Soprano recorder, key of C. 
Fingering system: German fingering (not Baroque). 
Construction / Material: Made of ABS resin (synthetic plastic), 3-piece body. 
Windway: Arched (curved) windway — this gives a bit more resistance when blowing, helping with breath control and producing a more expressive, wood-like tone than straight-windway plastic recorders. 
Toneholes: Double holes (thumb & finger holes doubled where appropriate) for standard recorder fingering options. 
Included Accessories: Typically includes a cotton case (bag), cleaning rod, fingering chart, and recorder cream / maintenance accessories. Yamaha Online Music Store+1
Intended Use Level: The “30-series” recorders (like YRS-31) are often seen as a step up from very basic student recorders — offering better tone projection, more expressive potential, and a more “professional” feel.