Despite the ring being "+5", what could sugest a cheap bonus, the real bonus is quite large, sometimes being even a boost of 300% of base buff (without ring, chaos roll test, going from 509 > 540 without ring, to 509 > 620 att).
Given how cheap this ring is, there no way to be a cor without this one. A rem size buff for less than a million, hurry up and grab one.
Can also get this one by exchanging the 6 paragons kis to spark npc, in option seven treasures.
As a heads up, atm it seems the rings are broken for some rolls if you also have the job bonus active. The only roll I've tested is Beast roll with Ifrit.
893 ATK normally. w/o job bonus it worked fine on all rolls, but with it, lucky#4 and 11 dropped it to 449/505 respectively.