The JP162 single French horn is designed for children as it is a ‘small wrap’ so it is essentially smaller than a full size horn, the reason for that is so a child can put their right hand correctly into the bell whilst maintaining the correct posture for playing.
There is still some debate amongst many French Horn teachers as to which ‘side’ to start new pupils on, i.e. the ‘Bb’ or the ‘F’ side, this is just basically different fingering for the same notes with the Bb side being easier to pitch rather than the F side. The JP161 is the Bb side and the JP162 is the F side, however both horns still read horn in F music and transpose a 5th which can be confusing for some!
As a horn player you have to learn both sides of the horn so it is worth checking with your proposed teacher that you buy the correct single horn as some teachers only teach the Bb side and others only the F side.