Undersea Tunnel B4 (iz_dun03) is a dungeon map of Episode 13.2 with monsters from level 14 to 53.
Map
Monsters
| Monster | Lv | HP | Base EXP | Job EXP | Element | Race | Size | Amount | Respawn | |
|---|---|---|---|---|---|---|---|---|---|---|
 | Phen | 26 | 3,347 | 17,850 | 11,300 | Water 2 | Fish | Medium | 45 | 1 s |
 | Hydra | 14 | 660 | 2,950 | 2,000 | Water 2 | Plant | Small | 40 | 1 s – 5 min 23 s |
 | Swordfish | 30 | 4,299 | 62,550 | 31,900 | Water 2 | Fish | Large | 40 | 1 s |
 | Marc | 36 | 6,900 | 49,400 | 31,250 | Water 2 | Fish | Medium | 40 | 1 s |
 | Marine Sphere | 28 | 3,518 | 23,050 | 14,200 | Water 2 | Plant | Small | 20 | 1 s |
 | Merman | 53 | 14,690 | 225,000 | 150,000 | Water 3 | Demi-Human | Medium | 3 | 30 min |
EXP per kill at this server's 50x rate.
Warps
| From | To | Arrive at |
|---|---|---|
| (29, 63) | Undersea Tunnel B3 iz_dun02 | (339, 328) |
| (264, 245) | Undersea Tunnel B5 iz_dun04 | (26, 27) |
Maps with a way here
Undersea Tunnel B3, Undersea Tunnel B5
Drops on this map
32 items from the monsters here
| Item | Best chance | From |
|---|---|---|
 Gill | 100% | Marc |
 Sharp Scale | 100% | Swordfish |
 Fish Tail | 100% | Phen |
 Tentacle | 100% | Hydra |
 Tendon | 100% | Marine Sphere |
 Detonator | 100% | Marine Sphere |
 Sticky Mucus | 100% | Hydra |
 Ancient Lips | 100% | Merman |
 Fin | 100% | Marc |
 Meat | 100% | Phen |
 White Herb | 70% | Marc |
 Lemon | 40% | Merman |
 Holy Water | 30% | Merman |
 Rough Oridecon | 20.3% | Merman |
 Blue Gemstone | 20% | Marc |
 Rough Elunium | 5% | Swordfish |
 Aquamarine | 4% | Merman |
 Mystic Frozen | 3.5% | Merman |
 Emveretarcon | 2.5% | Hydra |
 Katana [4] | 2.5% | Swordfish |
 Detrimindexta | 2% | Hydra |
 Chain [3] | 1% | Marine Sphere |
 Transparent Head Protector | 1% | Marine Sphere |
 Panacea | 0.5% | Hydra |
 Trident [2] | 0.3% | Merman |
 Unicorn Horn | 0.2% | Swordfish |
 Hydra Card | 0.1% | Hydra |
| Marc Card | 0.1% | Marc |
| Marine Sphere Card | 0.1% | Marine Sphere |
| Merman Card | 0.1% | Merman |
| Phen Card | 0.1% | Phen |
| Swordfish Card | 0.1% | Swordfish |