The new RockeTech bat includes the PowerArch ' exterior sleeve ' multi-wall design. Together they create a highly responsive hitting surface that includes a generous effective hitting area and superior feel. he TaperFlex contour is designed to optimize the flexural and vibration response of the bat by distributing the mass of the taper in such a way that a harmonic flexural response is achieved.Bat Specs:' -9drop' Light weight End Cap' Double Wall All Metal Barrel' USSSA Stamp