Choosing a catcher's mitt
Size: a 32" to 32.5" mitt for players under 12, 33" to 33.5" for 13 to high school, 34" for adults. Bigger is not better; a mitt the catcher can close quickly frames pitches and transfers faster.
Padding and break-in: pro mitts (All Star Pro Elite, Rawlings Heart of the Hide and Pro Preferred) are stiff and need real work to break in, then hold their shape for years. Mid-grade mitts (All Star S7 and Top Star, Rawlings R9 and Player Preferred, Mizuno Franchise) come softer. Youth mitts (Future Star, Renegade, Prospect, Future Elite) close on day one, which matters more than durability for a 9-year-old.
Web: most catcher's mitts use a closed or half-moon web. It is a matter of feel; the closed web is stiffer, the half-moon flexes more.
Which brand: All Star makes nothing but catcher's gear and its mitts are what most pro catchers wear; the CM3000 is the benchmark. Rawlings Heart of the Hide is the other pro standard. For a first mitt, the All Star Future Star or Rawlings Renegade at $45 to $80 is plenty.