during combat, the driver continues to navigate via a triplex auxiliary sight. The sight was developed from a similar device on the T-60 light tank. Both the BA-64 and BA-64B were powered by a four-cylinder GAZ petrol engine developed 50 hp (37 kW) at 2,800 rpm. The engine was particularly reliable and known for operating for extended periods even on low octane fuel and poor quality oil with minimal maintenance. Under wartime conditions it was capable of providing good operational service up to 15,000 kilometres without needing major repair. The BA-64 could be fitted with bullet-proof GK combat tyres, although these resulted in higher fuel consumption and reduced road speeds to 40 km/h. Red Army mechanics typically fitted standard tires from the GAZ-M1 passenger car with civilian tread to the BA-64 for use in convoys, long-distance road marches, and rearguard duties. An open-topped turret was fitted as standard to the BA-64 series, with a 7.62mm light machine gun mounted on a pintle to the right. The machine gun mount was designed for maximum elevation so it could engage low-flying aircraft or infantry in the upper floors of a building during urban combat. A very small number of BA-64s were fitted with a 12.7mm heavy machine gun in a larger, open-topped turret. This model included splash guards and armoured fillets on the hull roofline. Personal crew weapons, such as hand grenades, were also stored inside the vehicle's hull. The BA-64 underwent some minor modifications as the BA-64B. While the most noticeable of these changes were the new carburetor and the wider track, successive models of BA-64Bs also included firing ports, cylindrical sheet metal exhaust shields, an additional air intake atop the engine compartment, and an air intake for the driving compartment on the hull roof. Variants BA-64: Standard production model from 1942 to 1943, built on the chassis of a GAZ-64 jeep. Armed with a single 7.62mm Degtyaryov machine gun in an open-topped turret. BA-64B: Standard production model from 1943 to 1946, built on the chassis of a GAZ-67 jeep and incorporating a new carburetor, air intakes, and firing ports. Armed with a single 7.62mm Degtyaryov machine gun in an open-topped turret. BA-64D: Fire support variant of the BA-64B armed with a single 12.7mm DShK heavy machine gun. Prototype only, rejected due to space limitations. BA-64-126: Turretless staff car variant, did not progress beyond the concept phase. Seated a driver and