"Tactical-technical characteristics of the IS tank
- Full combat weight: 43-44 tons
- Crew: 5
- Armour
- Front: at least 120 mm thick, cast
- Side: at least 90 mm thick, rolled
- Floor and roof: at least 20 mm thick, rolled
- Rear: at least 60 mm (at an angle of 45 degrees), rolled
- Turret: at least 100 mm, cast
- Armament:
- 85 mm gun with AA gun ballistics
- 3 DT machineguns, one coaxial, one in the front hull, operated by the driver, one in the rear of the turret (doubles as AA machinegun).
- 2 submachineguns
- Ammunition:
- At least 60 85 mm rounds
- At least 3000 machinegun rounds
- At least 500 submachinegun rounds
- At least 25 F-1 grenades
- 600 hp V-2K engine with an inertial starter
- Top speed of 35-37 kph
- 500 kg capacity of main fuel tanks
- Transmission: mechanical, normal type, with a planetary turning mechanism instead of friction clutches. Planetary final drives.
- Observation devices:
- Commander's observation cupola with triplex observation devices in the sides and an English periscope in a rotating hatch.
- 3 triplex observation devices: 1 for the driver and two in the sides of the turret.
- 3 English type periscopes, of them:
- 2 for the driver
- 1 for the loader in the turret
- Communication equipment:
- External: 10R radio in each tank.
- Internal: intra-tank communication device
- Turret ring diameter: at least 1800 mm.
GBTU Chief, Lieutenant-General of the Tank Forces, Vershinin
GBTU Tank Department Chief, Engineer-Colonel Afonin
May 4th, 1943"