Easton FMJ 500 spine Aluminum Shafts - 12 Pack - Made with a tough carbon core and durable alloy jacket for increased strength and bone crushing performance. Straightness tolerance of +-.002in 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