The P-40 "Armour" or 1S12 (also referred to by the NATO reporting name "Long Track" in the west) is a 3-D UHF radar developed and operated by the former Soviet Union.

The P-40 started development in 1960 and by 1962 the radar had completed state trials and in 1963 was accepted into service by the anti-aircraft troops of the Soviet armed forces.

[1] In 1965 the P-40 gained the GRAU designation 1S12 as it was adopted as the target acquisition radar of the 2K11 Krug mobile anti-aircraft defence system.

The P-40 was developed by Scientific Research Institute #208 GKRE, which later became known as NIIIP of Minradioprom, OKB-588 (later Lianozovskiy Electromechanical Plant, LEMZ) also assisted in the production of the prototype.

[2] The P-40 used the AT-T artillery tractor with tracked chassis, fitted with a 12-cylinder 4-stroke diesel engine with an output of 342 kW (465 hp) and producing a top speed of 55 km/h.