To refine a equipment you need a refinment stone, there are 3 differnt stones, as follow:
- LVL 1 stone (1-3)(Basic)
- LVL 2 stone (4-6)(Intermediate)
- LVL 3 Stone (7-9)(Advanced)
Every LVL is a checkpoint, so that you equipment will not fall down to a lower level. So if you reach lvl 2 your equipment cannot get a refinment lvl 4 or lower.