Jammer-finder

A techno-magical device that senses the presence of spelljammers at a safe range. 
Spelljammers, magical interstellar craft, are notoriously difficult to see with normal sensors. This would not be an issue except that the interaction of a warp field and a jammer field are mutually fatal. You will never feel it. The chances of a collision are miniscule, but present, and we know about it because it has happened.
Be safe, be covered if you plan to travel anywhere near the Magic Zone.
A counterpart device the warp-finder is made for spelljammers.
Category:Outsiders
Category:Supernatural
Category:Technology