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.
I use everything in atack speed because in early game you can notice how fast he is, and in late game you will simply not die because of the lifesteal.
Think fast and do the berserker's boots, them the zeal. If the game takes to long sometimes i sell doran's blade to buy some defense and life ussually Randiun's Omen.
Flash don't need any explanition. I use the clarity because i like to have stun always ready and spam volley. It is very nice to have if u have spend all your mana in frost shot.