Blessing fires on heal cast. On a piece that carries it it reads: Heals you cast grant the healed ally +{value}% Power for 4 s.

Word for word it is Heals you cast grant the healed ally +{value}% Power for 4 s, and the number in it grows with the gear: 8 to start, 0.3 more for every item level.

0 bases carry it.