Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This build works pretty well if you are going to be an Rammus initiator, you got plenty of armor and resistance which gives you pretty nice amount of effective hp amount.
If you got mages in the opposite yeam, you just purchase guardian angel or another one banshees veil instead of one of sunfire capes.