LOUISVILLE MLB PRIME SIGNATURE SERIES RA13 RONALD ACUNA JR. GAME MODEL BASEBALL BATA Rookie of the Year, an All Star appearance and a Silver Slugger all before the age of 23. Ronald Acuna Jr. and his MLB Prime Signature Series RA13 are ready to add to that already impressive resume. Pairing an AJ10 handle and I13 barrel with a flared knob, this high gloss black handle and natural barrel bat is nothing short of flawless. The MLB Prime Signature Series lineup offers all players a chance to step up to the plate with bats big league