Midi-chlorian Scouter

A Midi-chlorian Scouter is a device used by the Jedi Order in the Clone Wars to scout potential Jedi, if a child's reading is 10 or higher they got accepted, anything lower was ignored, these devices were created by Republic Scientists in 32 BBY and were tested for a little over 10 years before being made public to the Jedi Order. Jedi using these were Jim Logan Ahsoka Tano and Anakin Skywalker. . The scouters came in 3 colors, "Red, Blue and Green." A black version was made, but was destroyed after an attack by the CIS.

Behind the scenes
The Midi-choloran scouters are based off of scouters from the Dragon Ball series.