I don't know about those kind sorry, they came on the market for younger kids etc after mine was older so he never used one. I thought you meant a chest protector like in catching gear.
Maybe someone else can help!
Edited to add: I will say though that the under armour heat gear made my son hotter he said, he just wore a tshirt under his jersey if necessary(but who knows, catchers are crazy anyway). (OT.He did use the cold gear though) I think I would try the shirt first, probably more comfortable for pitchers.