Rm. 4 Key is an item in the “Plot advancement” category (Key Items).
In-game descriptions
| Ruby / Sapphire · Emerald | A key that opens a door inside the ABANDONED SHIP. |
|---|---|
| FireRed / LeafGreen | A key that opens the door to Room 4 inside the ABANDONED SHIP. It is old and looks easily broken. |
Where to find it
Not placed on the atlas maps (so far: Red/Blue and Generation 3).
Sources : PokeAPI (items, item_flavor_text, machines) · atlas · pokeemerald species_info.h