Bud hardener yes, never had such hard nugs before. But after close examination of the growth(if used before day 14 of 12/12) it seems like it directs all of its energy to making calyx's. As you guys are aware each calyx has atleast 1 pistol(some have 3, 4 or 5) so you get huge(from growing so many calyx's) rock hard nugs but the downside is when harvested you get very hair buds.