guide
Item options in MU
Besides its level (+), a MU item can have up to three basic options: Skill (unlocks the weapon's skill), Luck and the additional option, which rises in steps. The server's option file shows how much each step is worth.
The three basic options
- Skill: on weapons, unlocks the weapon's own skill (each weapon page shows which).
- Luck: in the Season 4 option file we analysed, the Luck group has a value of 5 for weapons, armor, shields and wings; it also adds a bonus to Jewel of Soul and Chaos Machine success rates.
- Additional option: raised with the Jewel of Life. In the analysed file each step is worth 4 on weapons, staffs and armor and 5 on shields.
How many steps the additional option can have
With 7 steps of 4, the additional option reaches +28; with 4 steps, +16. That is why “+28” and “+16” show up so often in searches.
| Season 3 | Season 4 | Season 6 | Season 20 | |
|---|---|---|---|---|
| Max additional option steps | 7 | 7 | 7 | 4 |
| Jewel of Life rate (%) | 50 | 50 | 50 | 60 |
Values found in the GameServerInfo files of each emulator package we analysed. They are not official rules: every server sets its own.
What about excellent options?
Excellent options are another layer that only excellent items have. See the excellent items guide. Ancient, socket and 380 items also have their own options.
FAQ
What does +28 mean in MU?
It is the additional option at its maximum when the server allows 7 steps of +4. It is raised with the Jewel of Life.
What does Luck do on an item?
In the Season 4 option file we analysed, Luck has a value of 5 and also raises the success chance of the Jewel of Soul and the Chaos Machine.
Play MU? MU Éter is a Season 4 server with its own systems. Discover MU Éter · MMO GRID is maintained by the MU Éter team.
Sources
- Item/ItemOption.txt from the Season 4 emulator
- GameServerInfo - Common.dat from the Season 3, 4, 6 and 20 emulators
- MuBattle Season 4 source code (Jewel of Life)
Demand snapshot: SNAP-20261001-1040 · Data extracted on 2026-10-01