Absolutely amazing Lunar Traverse Gravimeter, a production representative example of the same gravimeter used on the lunar surface during the Apollo 17 mission. Gold plated unit measures approximately 9 x 17 x 8, standing on three small legs, with a rotating carrying handle at the top, which was also used for locking the unit on the Lunar Rover. Gravimeter has no front panel so that the internal workings of the device may be viewed. The TGE had a nine-digit display to read out gravity and internal temperature. Also included is the gold-plated phase lock loop, 7 x 6.5 x 4, serial numbers 010 and 011, as well as the plated spare battery pack assembly, serial number 010. Built by the Instrumentation Laboratory at MIT, the purpose of the gravimeter was to measure the moon's gravitational field using a precise Vibrating String Accelerometer (VSA). While on the Moon, astronauts would move the device to different locations and take readings of the gravitational force. Packaged as part of Apollo 17’s ALSEP package, the gravimeter was housed on the geopallet of the lunar rover. Only three other gravimeters are in existence, one left on the lunar surface by Apollo 17, the mission’s back-up at the Smithsonian, and one other at Columbia University.