This is not quite as large as a baseball, but fits in the hand with fingers wrapped around it in perfect way, and I might guess it was a homemade version used for backyard baseball, though I don't know for certain. Definitely it was hand-sewn, white leather with blue thread, and it looks like it took at least one good smack that was contributed to it's wonky shape now. Personally, I've always found stitching on baseballs super beautiful in and of itself and also as it calls attention to the  construction of the skin of the ball from two pieces leather laid in opposite directions, and one can just feel the labor involved in piercing the leather and pulling the stitches on this one, which I just really like as a thing.

Approx 2 3/4” x 2 5/8”, sound and sturdy. I have not tensted it, but perhaps ideally suited for throwing a curve ball!