roots organics HPK does this, I'd also pick up some buddha bloom too since it has worm castings and bat guano and carbohydrates to boost up the buds...
but remember it's not exactly going to force them to finish, its just going to give them what they need to finish off well.
Ya I use budswell every other feeding for the first 5-6 weeks of flowering then i switch to overdrive during the last 2 weeks of flowering. I am also gonna try MOAB (mother of all blooms) my bud uses that insead of ovrdrive and does good.