The Extension is a drone to allow Renala to access doors and other computer systems' close range systems as if she stood beside it. It opens up a direct high-bandwidth wireless connection to enable her to use it as a virtual device functioning exactly like her omni-tool's internal transmitters. In simple terms, it's a proxy so that Renala can be safely in cover while performing her magic on doors.
The device itself is not a pretty sight, as it's a ball of small components held together by tense wires and insulating tape. The shield emitters are the most easily spotted on the outside. It's about the size of a baseball.
Unlike Renala's other creation, this drone does make use of kinetic barriers and levitation to get around. The reason for that is that near-field communications may require it be higher up on a door before Renala can use it as a proxy.
As of October 2185, Renala has not yet used the device. She prepared it for their assault on Avoren Security's base, but there was no reason to use it. Some of the parts are expensive and difficult to procure, making her hold it until absolutely necessary.