VIM was a series of rifle-mountable induction metal detectors. The 1942 model of the VIM-203 with a rectangular search coil was used by the Red Army during the Great Patriotic War. When the search coil of the metal detector hovers over a metal object, the tone in the sapper’s headphones changes. The distance between the metal object and the coil at which the sapper begins hearing signals depends on several factors: the size and shape of the object, the nature of the terrain between the frame and the object (air, dry or wet ground, water), the presence of metal in the soil around the mine. A mine with a metal body was detected on average at a depth of up to 0.6 meters. The estimated operating time without changing batteries was up to 30–35 hours.
The VIM-203 was named so because the search coil could be attached to both a special rod and directly onto the barrel of a standard Mosin-Nagant rifle, which remained ready for combat. This made the mine detector lighter, more compact and more versatile.
By design, the mine detector consisted of a search coil that could be mounted onto a rifle or rod, a control unit that was mounted on the coil itself, and headphones transmitting a signal from the unit. VIM-203 mine detectors were produced at the Ordzhonikidze factory. In total, during the war, the Red Army received more than 247 thousand military metal detectors of all modifications.
These mine detectors also played an important role on the Karelian Front. A large number of mines were laid in Petrozavodsk. From the memoirs of the commander of the 31st separate Marine Battalion, Ivan Molchanov:
