When I bought the violin, I bought also this rosin, what I didn't know is that with the violin also came a rosin.
At first I thought that I wasted a bit of money buying a second rosin, but I really had a lot of problems with the rosin that came with the violin. I was unable to "brush" (don't know word in english) the bow with the rosin.
So I just tried with this rosin and it was perfect, I immediatly threw to the bin the rosin that came with the violin, and I'm only using this one.
One day it fell to the floor and broke in several pieces, I gave it a little heat with the microwave and put them together again and it is still useful.