Yes. A character can use it once per turn.

From the Player's Guide:
No.

From the Player's Guide:
Since it does not have the continual keyword, the effect is ignored while the object is carried.

From p. 18 of the Blackest Night Rulebook:

Thanks for the clarification. Might want to throw in that "Once per turn" addendum on the first post. And I can never remember what continual means. Anyway, thanks again.

All 3D objects are now marked as such, and I've put where they all came from (to the best of my memory). I've also put a description of what 'Continual' means in the initial post, and edited the Telephone Booth description.

Thanks, WakandaMan!

Just added the Bucket of Water, White Lantern and Crimson Gem of Cyttorak to the list.

The "continual" rule doesn't exist anymore :

"SPECIAL OBJECTS
[...]
The abilities of the special object continue whether the object is being held or occupying a square, though some objects may specify that their effects are ignored when they are held."

(from the rulebook)

The line "This object has no effect when held." has been added to the wording of the following special objects :
Aerial Baffler
Dark Cauldron
Dynamostat
Eleha'al Vine
Force Field Generator
Kinetic Absorber
Laser Turret
Opened Hydrant
Shield Disruptor
Structural Integrity Field
Telephone Booth

A lot of special objects' texts have also been modified by replacing "carrying" with "holding" when refering to an object. And there are other minor wording changes that adapt to the latest ruleset.

(a link to the Golden Age PG, it's more complete than this post)

Thanks for that Drunky.

However, the PG you linked me to still has the word Continual on many objects and doesn't have the edits that you mentioned, so I'm a little confused.

Oops, I copied and pasted the wrong link, sorry. It should link to the right one now.

Thanks! I'll fix the OP up with all the changes.