"Critical strike", "Life Steal"
Boots and Magic Penetration
Ability Power and Defence
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.
Teemo is very good at Meta of ADC and Assassin. Now we also have "Critical Strike" and "Life Steal" for apc to replace adc bot. So why don't we try this? (May be that is why riot nerf Devourer from ranged champion). Magic Penetration is very good for Teemo but it not increase "AP Critical Strike" so be careful