Mizuno Silhouette - 13 Fastpitch Softball Bat Approved for play in all associations - ASA - USSA - NSA - ISA - ISF X-Zone technology adjusts composite angles in 10 specific zones to create higher exit speeds across the barrel. One Piece Double wall barrel with Black Array carbon for shorter break in period to maximum performance. Anti-Shock construction add layers in the taper to reduce shock and increase durability. Speed-Helix grip provides comfort and durability.