They are aluminum, I think, 3 fletch, don't know the spine, have to look on the box and try to figure it out, I guess.
Sam, if they are aluminum, there will be a number like 1916, 2018 etc. That will be the "spine". Don't quite understand the ins and out of the aluminum but it's got to do with the wall thickness.
The screw in points come in a variety of weights as well. You can really fine tune it by varying the weight of the point and the length of the shaft.
I generally shoot wood, but do have some aluminum and fiberglass shafts.