perfect red and blue mile?
 

what is the difference between the red and blue miles. Seems like they do the same thing but 1 cost more. I'm confused :(

Red miles prevent breakage.


Blue miles prevent them from downgrading.


Wiki is your friend :nahnah:

can you put them both in the slots at the bottom at the same time while your refining your weapon so as to have no breakage and degradation?

Yes, they go in different slots.


Highly recommended that you use both at the same time or your item will either break or downgrade all the way to +0. The third slot is for Gold-Miles that increase chance of success by about 15%