Has a chance to seal an affix instead of upgrading it. The sealed affix is moved to its own slot, leaving its old slot open for you to add a new affix.

The sealed affix cannot be modified further and an item can have a maximum of one sealed affix.

Chance to seal is higher when crafting on affixes of lower tiers, and is also higher for exalted items and items with more affixes.

Press [F] to open the Crafting Panel.