Victory Sport 355 spine Carbon Shafts - 12 Pack - A parallel taper design for superior accuracy, high FOC, and faster arrow recovery in flight. A thinner, weaker tail section reduces wind drift and improves clearance during launch, while a thicker front section increases FOC and improves down range accuracy. Weight tolerance: .5 grains. Spine tolerance: .006in. 355 (7.5 gpi)