» [b]Scouters[/b] - were created by Frieza's scientists. It was made to help determine how strong a person was. It's worn around one eye and can detect power levels from miles away. It gives the power level in the form of a number, and so they compare the number to their own to see where they stand if they were to fight that person. Numbers will show up on the glass part around your eye so that they can read it easily while moving and navigating. It can also be used to hide or find people, just locate their power level and move away or towards it. Although sometimes since its only a machine, it'll go haywire and start giving inaccurate readings or if the power level becomes too high, sometimes the scouter will blow up. The Scouter comes in a variety of colors: Green, Pink, Purple, and Blue. It identifies the model version, green is earliest, and blue is latest. Since the Z Fighters have the ability to change their power levels, they can manage to hide from the scouter by lowering their power levels, so that the scouter can't pick them up. This is a major advantage when trying to escape or sneak around those who wear the scouter. The way that works is the individual suppresses his energy to the point that his body doesn't fume out the frequency, rendering the scouter to read 0, or more depending on the characters skill at this camouflage. Later in the series people like Vegeta learn how to sense people's power without using a scouter. This doesn't give any kind of number but it still works. Around the late Frieza Saga the Scouters became useless when, a fighter's strength began to be too strong to measure and they blew up.