What age is this for?
S size is 8.5 inch, fits for 2~4 Years. M size is 9.5 inch, fit for 5~7 Years.
Does this come as one glove or a pair?
It comes single one.
What does a right hand thrower glove mean? Does this glove go on the right or left hand?
Means you wear the glove on your left. Your prominent hand is your throwing hand. So if you write right handed, commonly will throw right handed, glove on left.
Does it come with the the ball ?
No, it doesnt include the ball, but it comes with a drawstring bag.