[1] There two sets of MAG instrument suites, and they are both positioned on the far end of three solar panel array booms.
[1][2] The MAG instrument is designed to detect the magnetic field of Jupiter, which is one of the largest structures in the Solar System.
[7] The MAG instrument was delivered to Lockheed Martin Space Systems' facility in Denver, Colorado, United States for integration into the Juno spacecraft by NASA's Goddard Spaceflight Center (GFSC) in October 2010.
[6][8] MAG was overall designed and built at the NASA Goddard Space Flight Center (GFSC) in Greenbelt, Maryland.
The fluxgate magnetometer (FGM) is similar to previous instruments flown on spacecraft like the Voyagers, Magsat, Active Magnetospheric Particle Tracer Explorers, Mars Global Surveyor, etc.
[6] Magnetometers related to Juno include ones on MAVEN, MGS, Voyager, AMPTE, GIOTTO, CLUSTER, Lunar Prospector, MESSENGER, STEREO, and Van Allen Probes.
[11] At one point, JPL was working on including a Scalar Helium Magnetometer on Juno, in addition to the FGM and ASC suite.