4/2

4/2 refers to the 4 primary / 2 secondary affixes that most rare and legendary items roll with in Diablo 3 or Reaper of Souls, with the Loot 2.0 itemization system. The 4/2 system replaced a more randomized system in Diablo 3 vanilla, where affixes were not assigned to primary or secondary, and items could roll up to 6 affixes, selected almost entirely at random.

This gave rare/legendary items in D3v much wider variance, with some complete junk and a tiny percentage coming in with super high quality in the (impossible) equivalent of a Loot 2.0 item with 6 primary affixes.

The 4/2 rule makes it impossible for items in Reaper of Souls to be super high quality. For instance, Diablo 3 had occasionaly quinfecta items (or even "septfecta") with five ideal affixes.

Hypothetical Rare Ring/Amulet/Gloves from Diablo 3 vanilla:

• Critical hit Damage
• Critical hit Chance
• Increased Attack Speed
• +Mainstat
• Damage
• Vitality or All Resistance or Area Damage, etc.

That's six primary affixes, an impossible roll in Loot 2.0, but one that existed in D3v.