IS is a Soviet, tier 7, heavy tank.
The IS is the first of the Iosef Stalin tanks avaialble to players. It fares well against enemines at close range. The tank itself is similar to the KV-1S, and comes with armour to boot. The tank cares over the 122mm gun of the KV-1S, and stock, you'll mostly use said gun. The tank fares well in tier 7 matches, and has enough Hit Points to take some hits, but don't rely on it to save you. Due to the tanks guns being centered around damage, the IS can be dificult to play in tier 9 matches, where it can't snipe the lower plates or bounce many shots. In cases of tier 9 matches, try and stay back and hit the enemies tier 7's and, if possible, tier 8's.
The tanks powerful attributes are taken to new levels with the next tank in-line, the IS-3.