EDIT: If you're here for information and don't want to scroll down, the Tactics Pearl is identical to the Signal Pearl except it has four charges and can be reused after only 10 minutes (instead of 20 hours). I'd presume you'd be able to get a new one once a week so that you could have one very long XP session, or several longer ones throughout the week. Pretty cool.
I have one of these from the NPC Promyvion quest, but I'm wary about trying it before I know exactly what it does. I presume it works just like the Signal Pearl except it has a shorter recast and only four charges? Or does he stay for a shorter amount of time?
Edited, Fri Oct 14 10:40:12 2005 by Marstead