As i mentioned in a previous post i am new so please help me out. I was told by the shop that i got my bow at to use 2415' s (Alum arrows). I guess i am trying to figure out what these numbers mean. I am having a hard time finding that number arrow locally and the cost is pretty high for a dozen. I am looking for alternatives and how i can tell they are alternatives by what the number " 2415" means. Also, i went to look at some carbon arrows and they were 60/70' s? what does this mean. thanks.