EW Drones require the Electronic Warfare Drone Interfacing skill, and are pretty much what they sound like - drones that use EW instead of damage. These can become insanely handy if you're in a gatecamp or other fleet situation, using your drones for your EW capability while your other weapons do the damage. However, to be used properly they do require a bit of micromanagement so consider this before you train or fit for a large fleet action.

The side benefit (some would argue primary benefit) of training the EW drones skill is that it gives a 3 kilometer bonus to drone control range for drones of all types. Think of it as “Advanced Scout Drones” except that the bonus isn't as good and takes longer to train. Still, it's worth getting up to level IV because your drone control range will be about 62km without drone link augmentors.

Note: Only carry ECM Drones (eg. Hornet EC-300) with you, as the other forms of ewar drones (eg. Tracking Disruptor, Stasis Web) suffer from a stacking penalty and are impractical.