2A45 and 2A45M are the respective GRAU designations of the Sprut-A and Sprut-B (Russian for octopus or kraken[1]) Soviet smoothbore 125 mm anti-tank guns.

The 2A45M was created in the late 1980s by the Petrov Design Bureau at Artillery Plant Number 9 (OKB-9), which was also responsible for the 122 mm howitzer 2A18 (D-30).

A feature of the Sprut-B is its integrated engine, which can propel the gun on relatively flat surfaces (up to 15 degrees of slope) and at 14 km/h on roads.

Such guns are known in Russian as "self-moving" (самодвижущиеся) in contrast to self-propelled (самоходные), and outside of battle it is towed by an MT-LB.

[2] The barrel features a thermal sleeve to prevent temperature changes affecting the accuracy.