It is an overall buff to armor, aiming time and HP
T1 Heavy Tank
- Enhanced front armor for T1D6 turret
- Dispersion of the 76 mm Gun M1A1 when rotating the turret reduced by 25%
- Changed the aiming time of the 3-inch Gun M7 from 2.3 to 2 s
- Changed the aiming time of the 76 mm Gun M1A1 from 2.3 to 2 s
- T1D6 turret view range changed from 330 to 350 m
- The maximum reverse speed changed from 10 to 14 km/h
- Durability with T1D5 turret changed from 820 to 860 HP
- Durability with T1D6 turret changed from 860 to 910 HP
source – wotexpress