Chaff Seed

A Chaff Seed (攪乱の羽)|Kakuran no Hane (Chafu Shīdo)|lit. "Feather of Disturbance"}} is a type of radio jamming device.

Principles
They are thin sheets of metal about the size of the lead of a mechanical pencil with two thin wings, appearing like tiny helicopter rotors. They use a micro motor to float in the air using the structure of the seeds of plants in the family. They have the ability to float under their own power but can not withstand strong gusts of wind. They then jam electromagnetic signals and many of them are often used in unison to jam a large area.

Skill-Out Uprising
Komaba Ritoku had hundreds in his possession and originally planned to use them to knock out Anti-Skill's radios but instead used them during his battle with Accelerator to jam his electrode. Accelerator was able to overcome them by shooting off the clasp of a colored plastic sheet that was spread between two nearby buildings as a satellite countermeasure. This caused a sudden gust of wind which blew away some of the Chaff Seeds, due to the range of their signal having them become separated like that created a hole in the jamming and allowed the first-ranked esper to have access to his abilities again.