It's the emergency turn key for Schlage L-Series mortise locks in the L9040 function, the privacy set used on restrooms and patient rooms. The turn key drops into the emergency slot on the outside face so staff can release the privacy lock from the corridor side without a key cylinder. One caveat worth knowing before you order: on an L9040 with the outside occupancy indicator, the release is worked with a small flathead screwdriver instead, so the turn key isn't what that variation needs.

No. On the L9040 with the outside indicator, the emergency release is operated with a small flathead screwdriver, not an emergency turn. Buy the L583-233-458 turn key for plain L9040 privacy locks without the indicator; for the indicator version, a screwdriver from the toolbox is the tool.

Just the tool. The L583-233-458 is the emergency turn key on its own, the small key-shaped tool that releases an L9040 privacy mortise lock from the outside. It is not a lockset, not a cylinder, and it does not include trim or a lock body. If the mortise lock itself needs replacing, you're looking for an L9040 lockset, not this part.

One turn key works any L9040 privacy mortise lock without the outside indicator, so it isn't keyed to a specific door and there's no keying to specify. Most facilities stock a few, one per housekeeping or maintenance cart and a spare at the desk, rather than one per opening. The L583-233-458 is ordered as a single model with no options to pick.

Neither. The emergency turn key is ordered as one model, L583-233-458, with no handing, finish, or keyway to call out. It's a loose tool rather than a door-mounted part, so nothing about the opening changes what you order.