Easton 5mm FMJ 400 spine Carbon Shafts - 12 Pack - The FMJ Micro diameter 5MM Full Metal Jacket arrows offer maximum penetration. A 7075 aerospace aluminum over high-strength carbon adds kinetic energy and precision to improve penetration and broadhead accuracy. The aluminum jacket makes pulling shafts from targets easier than carbon-surfaced arrows. Lower friction and aluminum/carbon composition combine for pass-through impacts and easier to follow blood trails on tough big game. 5mm HIT 8-32 inserts included (16 grains) pre-installed 5mm X Nocks 5mm small diameter, High-strength carbon core with 7075-alloy metal jacket Easy target pull Straightness: .002in