Accelerator Module

Source
This item can be purchased for from  in Blade's Edge Mountains.

About
Using this item on the gates at Bash'ir Landing spawns an elite mob that can be beaten by a moderate-size party. Their loot tables include Apexis Crystals. When you use the Accelerator Module to summon the elite is will be consumed. It is best to collect a few Accelerator Modules to ensure you can summon a few if you die.