Echo Strike fires on nth hit. On a piece that carries it it reads: Every {count}th hit strikes a second time for {value}% of the first.

Word for word it is Every {count}th hit strikes a second time for {value}% of the first, and the number in it grows with the gear: 100 to start, 3 more for every item level, and it only goes off every 20 times you set it up.

0 bases carry it.