Superior Leather Armor's effects are swapped (at least in this situation): I encountered a Skeleton Horde.
Valeros, who drew the horde, faced an Ancient Skeleton. He failed the roll by 3, and had to discard 3 cards. I selected Superior Leather Armor, and buried it (to negate all damage).
I was then told to select two more cards.
I pulled the SLA out of my bury pile and recharged it instead. All damage negated.